The Iran-backed militant group blamed Israel for the deadly explosions, which targeted an extraordinary breadth of people and showed signs of being a long-planned operation. How the attack was executed is largely uncertain and investigators have not immediately said how the pagers were detonated. The Israeli military has declined to comment.

Here’s what we know so far.

Why were pagers used in the attack?

Hezbollah leader Hassan Nasrallah previously warned the group’s members not to carry cellphones, saying they could be used by Israel to track the group’s movements. As a result, the organization uses pagers to communicate.

A Hezbollah official told The Associated Press the exploded devices were from a new brand the group had not used before. The official, who spoke on condition of anonymity because he was not authorized to talk to the press, did not identify the brand name or supplier.

Nicholas Reese, adjunct instructor at the Center for Global Affairs in New York University’s School of Professional Studies, explains smart phones carry a higher risk for intercepted communications in contrast to the more simple technology of pagers.

This type of attack will also force Hezbollah to change their communication strategies, said Reese, who previously worked as an intelligence officer, adding that survivors of Tuesday’s explosions are likely to throw away “not just their pagers, but their phones, and leaving their tablets or any other electronic devices.”

How could sabotage cause these pagers to explode?

With little disclosed from investigators so far, multiple theories have emerged Tuesday around how the attack might have been carried out. Several experts who spoke with The Associated Press suggest that the explosions were most likely the result of supply-chain interference.

Very small explosive devices may have been built into the pagers prior to their delivery to Hezbollah, and then all remotely triggered simultaneously, possibly with a radio signal.

By the time of the attack, “the battery was probably half-explosive and half-actual battery,” said Carlos Perez, director of security intelligence at TrustedSec.

A former British Army bomb disposal officer explained that an explosive device has five main components: A container, a battery, a triggering device, a detonator and an explosive charge.

“A pager has three of those already,” explained the ex-officer, who spoke on condition of anonymity because he now works as a consultant with clients on the Middle East. “You would only need to add the detonator and the charge.”

After security camera footage appeared on social media Tuesday purporting to show one of the pagers explode on a man’s hip in a Lebanese market, two munitions experts also said that the blast appeared to be the result of a tiny explosive device.

“Looking at the video, the size of the detonation is similar to that caused by an electric detonator alone or one that incorporates an extremely small, high-explosive charge,” said Sean Moorhouse, a former British Army officer and explosive ordinance disposal expert.

This signals involvement of a state actor, Moorhouse said. He adds that Israel’s foreign intelligence agency, the Mossad, is the most obvious suspect to have the resources to carry out such an attack.

N.R. Jenzen-Jones, an expert in military arms who is director of the Australian-based Armament Research Services, agreed that the scale and sophistication of the attack “almost certainly points to a state actor,” and that Israel had been accused of carrying out such operations in the past. Last year, AP reported that Iran accused Israel of trying to sabotage its ballistic missile program through faulty foreign parts that could explode, damaging or destroying the weapons before they could be used.

How long was this operation?

It would take a long time to plan an attack of this scale. The exact specifics are still unknown, but experts who spoke with the AP shared estimates ranging anywhere between several months to two years.

The sophistication of the attack suggests that whoever is behind it has been collecting intelligence for a long time, Reese explained. An attack of this caliber requires building the relationships needed to gain physical access to the pagers before they were sold; developing the technology that would be embedded in the devices; and developing sources who can confirm that the targets were carrying the pagers.

And it’s likely the compromised pagers seemed normal to their users for some time before the attack. Elijah J. Magnier, a Brussels-based veteran and a senior political risk analyst with over 37 years experience in the region, said he has had conversations with members of Hezbollah and survivors of Tuesday’s pager attack. He said the pagers were procured more than six months ago.

“The pagers functioned perfectly for six months,” Magnier said. What triggered the explosion, he said, appeared to be an error message sent to all the devices.

Based on his conversations with Hezbollah members, Magnier also said that many pagers didn’t go off, allowing the group to inspect them. They came to the conclusion that between 3 to 5 grams of a highly explosive material were concealed or embedded in the circuitry, he said.

What else could have happened?

Another possibility is that malware could have been inserted into the operating system of the pagers — somehow causing the device batteries to all overload at a specific time, causing them to burst into flame.

According to a Hezbollah official and Lebanese security officials, the pagers first heated up and then exploded in the pockets, or the hands, of those carrying them Tuesday afternoon.

These pagers run on lithium ion batteries, the Hezboolah official said, claiming the devices exploded as the result of being targeted from an Israeli “security operation,” without elaborating further.

When overheated, lithium ion batteries can smoke, melt and even catch on fire. Rechargeable lithium batteries are used in consumer products ranging from cellphones and laptops to electric cars. Lithium battery fires can burn up to 590 C (1,100 F).

Still, Moorhouse and others noted that images and video footage seen Tuesday more strongly resembled the detonation of small explosive charge, not an overheating battery.

“A lithium ion battery fire is one thing, but I’ve never seen one explode like that. It looks like a small explosive charge,” said Alex Plitsas, a weapons expert at the Atlantic Council.

Among those pointing to the likelihood of a supply chain attack is Jenzen-Jones, who adds that “such a large-scale operation also raises questions of targeting” — stressing the number of causalities and enormous impact reported so far.

“How can the party initiating the explosive be sure that a target’s child, for example, is not playing with the pager at the time it functions?” he said.

The Iran-backed militant group blamed Israel for the deadly explosions, which targeted an extraordinary breadth of people and showed signs of being a long-planned operation. How the attack was executed is largely uncertain and investigators have not immediately said how the pagers were detonated. The Israeli military has declined to comment.

Here’s what we know so far.

Why were pagers used in the attack?

Hezbollah leader Hassan Nasrallah previously warned the group’s members not to carry cellphones, saying they could be used by Israel to track the group’s movements. As a result, the organization uses pagers to communicate.

A Hezbollah official told The Associated Press the exploded devices were from a new brand the group had not used before. The official, who spoke on condition of anonymity because he was not authorized to talk to the press, did not identify the brand name or supplier.

Nicholas Reese, adjunct instructor at the Center for Global Affairs in New York University’s School of Professional Studies, explains smart phones carry a higher risk for intercepted communications in contrast to the more simple technology of pagers.

This type of attack will also force Hezbollah to change their communication strategies, said Reese, who previously worked as an intelligence officer, adding that survivors of Tuesday’s explosions are likely to throw away “not just their pagers, but their phones, and leaving their tablets or any other electronic devices.”

How could sabotage cause these pagers to explode?

With little disclosed from investigators so far, multiple theories have emerged Tuesday around how the attack might have been carried out. Several experts who spoke with The Associated Press suggest that the explosions were most likely the result of supply-chain interference.

Very small explosive devices may have been built into the pagers prior to their delivery to Hezbollah, and then all remotely triggered simultaneously, possibly with a radio signal.

By the time of the attack, “the battery was probably half-explosive and half-actual battery,” said Carlos Perez, director of security intelligence at TrustedSec.

A former British Army bomb disposal officer explained that an explosive device has five main components: A container, a battery, a triggering device, a detonator and an explosive charge.

“A pager has three of those already,” explained the ex-officer, who spoke on condition of anonymity because he now works as a consultant with clients on the Middle East. “You would only need to add the detonator and the charge.”

After security camera footage appeared on social media Tuesday purporting to show one of the pagers explode on a man’s hip in a Lebanese market, two munitions experts also said that the blast appeared to be the result of a tiny explosive device.

“Looking at the video, the size of the detonation is similar to that caused by an electric detonator alone or one that incorporates an extremely small, high-explosive charge,” said Sean Moorhouse, a former British Army officer and explosive ordinance disposal expert.

This signals involvement of a state actor, Moorhouse said. He adds that Israel’s foreign intelligence agency, the Mossad, is the most obvious suspect to have the resources to carry out such an attack.

N.R. Jenzen-Jones, an expert in military arms who is director of the Australian-based Armament Research Services, agreed that the scale and sophistication of the attack “almost certainly points to a state actor,” and that Israel had been accused of carrying out such operations in the past. Last year, AP reported that Iran accused Israel of trying to sabotage its ballistic missile program through faulty foreign parts that could explode, damaging or destroying the weapons before they could be used.

How long was this operation?

It would take a long time to plan an attack of this scale. The exact specifics are still unknown, but experts who spoke with the AP shared estimates ranging anywhere between several months to two years.

The sophistication of the attack suggests that whoever is behind it has been collecting intelligence for a long time, Reese explained. An attack of this caliber requires building the relationships needed to gain physical access to the pagers before they were sold; developing the technology that would be embedded in the devices; and developing sources who can confirm that the targets were carrying the pagers.

And it’s likely the compromised pagers seemed normal to their users for some time before the attack. Elijah J. Magnier, a Brussels-based veteran and a senior political risk analyst with over 37 years experience in the region, said he has had conversations with members of Hezbollah and survivors of Tuesday’s pager attack. He said the pagers were procured more than six months ago.

“The pagers functioned perfectly for six months,” Magnier said. What triggered the explosion, he said, appeared to be an error message sent to all the devices.

Based on his conversations with Hezbollah members, Magnier also said that many pagers didn’t go off, allowing the group to inspect them. They came to the conclusion that between 3 to 5 grams of a highly explosive material were concealed or embedded in the circuitry, he said.

What else could have happened?

Another possibility is that malware could have been inserted into the operating system of the pagers — somehow causing the device batteries to all overload at a specific time, causing them to burst into flame.

According to a Hezbollah official and Lebanese security officials, the pagers first heated up and then exploded in the pockets, or the hands, of those carrying them Tuesday afternoon.

These pagers run on lithium ion batteries, the Hezboolah official said, claiming the devices exploded as the result of being targeted from an Israeli “security operation,” without elaborating further.

When overheated, lithium ion batteries can smoke, melt and even catch on fire. Rechargeable lithium batteries are used in consumer products ranging from cellphones and laptops to electric cars. Lithium battery fires can burn up to 590 C (1,100 F).

Still, Moorhouse and others noted that images and video footage seen Tuesday more strongly resembled the detonation of small explosive charge, not an overheating battery.

“A lithium ion battery fire is one thing, but I’ve never seen one explode like that. It looks like a small explosive charge,” said Alex Plitsas, a weapons expert at the Atlantic Council.

Among those pointing to the likelihood of a supply chain attack is Jenzen-Jones, who adds that “such a large-scale operation also raises questions of targeting” — stressing the number of causalities and enormous impact reported so far.

“How can the party initiating the explosive be sure that a target’s child, for example, is not playing with the pager at the time it functions?” he said.

U.S. officials said that Navy Special Warfare Operator 1st Class Christopher J. Chambers was boarding the boat on Jan. 11 and slipped into the gap created by high waves between the vessel and the SEALs’ combatant craft. As Chambers fell, Navy Special Warfare Operator 2nd Class Nathan Gage Ingram jumped in to try to save him, according to U.S. officials familiar with what happened.

The criminal complaint unsealed Thursday in U.S. District Court in Richmond alleges that the four defendants were transporting suspected Iranian-made missile components for the type of weapons used by Houthi rebel forces in recent attacks.

“The flow of missiles and other advanced weaponry from Iran to Houthi rebel forces in Yemen threatens the people and interests of America and our partners in the region,” Deputy Attorney General Lisa Monaco said in a news release.

“Two Navy SEALs tragically lost their lives in the operation that thwarted the defendants charged today from allegedly smuggling Iranian-made weapons that the Houthis could have used to target American forces and threaten freedom of navigation and a vital artery for commerce,” Monaco said,

Muhammad Pahlawan is charged with attempting to smuggle advanced missile components, including a warhead he is accused of knowing would be used by the Houthi rebels against commercial and naval vessels in the Red Sea and surrounding waters. He is also charged with providing false information to U.S. Coast Guard officers during the boarding of the vessel.

Pahlawan’s co-defendants — Mohammad Mazhar, Ghufran Ullah and Izhar Muhammad — were also charged with providing false information.

The Iran-backed militant group blamed Israel for the deadly explosions, which targeted an extraordinary breadth of people and showed signs of being a long-planned operation. How the attack was executed is largely uncertain and investigators have not immediately said how the pagers were detonated. The Israeli military has declined to comment.

Here’s what we know so far.

Why were pagers used in the attack?

Hezbollah leader Hassan Nasrallah previously warned the group’s members not to carry cellphones, saying they could be used by Israel to track the group’s movements. As a result, the organization uses pagers to communicate.

A Hezbollah official told The Associated Press the exploded devices were from a new brand the group had not used before. The official, who spoke on condition of anonymity because he was not authorized to talk to the press, did not identify the brand name or supplier.

Nicholas Reese, adjunct instructor at the Center for Global Affairs in New York University’s School of Professional Studies, explains smart phones carry a higher risk for intercepted communications in contrast to the more simple technology of pagers.

This type of attack will also force Hezbollah to change their communication strategies, said Reese, who previously worked as an intelligence officer, adding that survivors of Tuesday’s explosions are likely to throw away “not just their pagers, but their phones, and leaving their tablets or any other electronic devices.”

How could sabotage cause these pagers to explode?

With little disclosed from investigators so far, multiple theories have emerged Tuesday around how the attack might have been carried out. Several experts who spoke with The Associated Press suggest that the explosions were most likely the result of supply-chain interference.

Very small explosive devices may have been built into the pagers prior to their delivery to Hezbollah, and then all remotely triggered simultaneously, possibly with a radio signal.

By the time of the attack, “the battery was probably half-explosive and half-actual battery,” said Carlos Perez, director of security intelligence at TrustedSec.

A former British Army bomb disposal officer explained that an explosive device has five main components: A container, a battery, a triggering device, a detonator and an explosive charge.

“A pager has three of those already,” explained the ex-officer, who spoke on condition of anonymity because he now works as a consultant with clients on the Middle East. “You would only need to add the detonator and the charge.”

After security camera footage appeared on social media Tuesday purporting to show one of the pagers explode on a man’s hip in a Lebanese market, two munitions experts also said that the blast appeared to be the result of a tiny explosive device.

“Looking at the video, the size of the detonation is similar to that caused by an electric detonator alone or one that incorporates an extremely small, high-explosive charge,” said Sean Moorhouse, a former British Army officer and explosive ordinance disposal expert.

This signals involvement of a state actor, Moorhouse said. He adds that Israel’s foreign intelligence agency, the Mossad, is the most obvious suspect to have the resources to carry out such an attack.

N.R. Jenzen-Jones, an expert in military arms who is director of the Australian-based Armament Research Services, agreed that the scale and sophistication of the attack “almost certainly points to a state actor,” and that Israel had been accused of carrying out such operations in the past. Last year, AP reported that Iran accused Israel of trying to sabotage its ballistic missile program through faulty foreign parts that could explode, damaging or destroying the weapons before they could be used.

How long was this operation?

It would take a long time to plan an attack of this scale. The exact specifics are still unknown, but experts who spoke with the AP shared estimates ranging anywhere between several months to two years.

The sophistication of the attack suggests that whoever is behind it has been collecting intelligence for a long time, Reese explained. An attack of this caliber requires building the relationships needed to gain physical access to the pagers before they were sold; developing the technology that would be embedded in the devices; and developing sources who can confirm that the targets were carrying the pagers.

And it’s likely the compromised pagers seemed normal to their users for some time before the attack. Elijah J. Magnier, a Brussels-based veteran and a senior political risk analyst with over 37 years experience in the region, said he has had conversations with members of Hezbollah and survivors of Tuesday’s pager attack. He said the pagers were procured more than six months ago.

“The pagers functioned perfectly for six months,” Magnier said. What triggered the explosion, he said, appeared to be an error message sent to all the devices.

Based on his conversations with Hezbollah members, Magnier also said that many pagers didn’t go off, allowing the group to inspect them. They came to the conclusion that between 3 to 5 grams of a highly explosive material were concealed or embedded in the circuitry, he said.

What else could have happened?

Another possibility is that malware could have been inserted into the operating system of the pagers — somehow causing the device batteries to all overload at a specific time, causing them to burst into flame.

According to a Hezbollah official and Lebanese security officials, the pagers first heated up and then exploded in the pockets, or the hands, of those carrying them Tuesday afternoon.

These pagers run on lithium ion batteries, the Hezboolah official said, claiming the devices exploded as the result of being targeted from an Israeli “security operation,” without elaborating further.

When overheated, lithium ion batteries can smoke, melt and even catch on fire. Rechargeable lithium batteries are used in consumer products ranging from cellphones and laptops to electric cars. Lithium battery fires can burn up to 590 C (1,100 F).

Still, Moorhouse and others noted that images and video footage seen Tuesday more strongly resembled the detonation of small explosive charge, not an overheating battery.

“A lithium ion battery fire is one thing, but I’ve never seen one explode like that. It looks like a small explosive charge,” said Alex Plitsas, a weapons expert at the Atlantic Council.

Among those pointing to the likelihood of a supply chain attack is Jenzen-Jones, who adds that “such a large-scale operation also raises questions of targeting” — stressing the number of causalities and enormous impact reported so far.

“How can the party initiating the explosive be sure that a target’s child, for example, is not playing with the pager at the time it functions?” he said.

The service members were identified as Sgt. William Jerome Rivers, 46, of Carrollton, Georgia; Spc. Kennedy Ladon Sanders, 24, of Waycross, Georgia; and Spc. Breonna Alexsondria Moffett, 23, of Savannah, Georgia.

President Joe Biden said the troops were killed by “radical Iran-backed militant groups operating in Syria and Iraq” and an investigation has been launched into the incident.

The deaths at a base in Jordan yesterday are the first in months of attacks by Iran-backed militants since the Israel-Hamas war began, though Iran sought to distance itself from the strike.

Biden is still “working through options” after he vowed to retaliate for the drone attack, White House National Security Council spokesperson John Kirby told NBC’s “TODAY” show.

For more on this story go to NBCNews.com.

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Biden ‘working through' retaliation options after Iran-backed militants kill 3 US troops

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Biden says US ‘shall respond' after 3 troops killed by drone strike in Jordan

John Kirby, the National Security Council’s coordinator for strategic communications, said in an interview on NBC’s “TODAY” show that the U.S. will do “what we have to do to protect our troops in our facilities.”

“What the options are available to the president — we’re still working through that, he’s still working his way through that,” Kirby told co-anchor Savannah Guthrie. “And I don’t want to close down any decisions based on it on his behalf.”

Kirby said while the administration doesn’t want a wider war with Iran or in the middle east, it’s aware that Tehran is backing militant groups in the region with resources and providing them with intelligence “that allows these groups to do this.”

“We’re taking that very seriously. We don’t want a wider war with Iran. We don’t want a wider war in the region, but we got to do what we have to do,” he added.

With an increasing risk of military escalation in the region, U.S. officials were working to conclusively identify the precise group responsible for the attack, but they have assessed that one of several Iranian-backed groups was behind it.

Biden said in a written statement over the weekend that the United States “will hold all those responsible to account at a time and in a manner (of) our choosing.” Defense Secretary Lloyd Austin said “we will take all necessary actions to defend the United States, our troops, and our interests.”

Iran-backed fighters in east Syria began evacuating their posts, fearing U.S. airstrikes, according to Omar Abu Layla, a Europe-based activist who heads the Deir Ezzor 24 media outlet. He told The Associated Press that the areas are the strongholds of Mayadeen and Boukamal.

Iraq Jan 23

US strikes Iran-backed militias in Iraq after series of attacks on American forces

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Iran's ‘brazen' strikes around the Middle East send a message to Israel and the U.S., analysts say

U.S. Central Command said at least 34 troops were injured by the one-way attack drone, with eight flown out of Jordan for follow-up care. It described the eight as being in stable condition.

The large drone struck a logistics support base in Jordan known as Tower 22. It is along the Syrian border and is used largely by troops involved in the advise-and-assist mission for Jordanian forces.

Central Command said approximately 350 U.S. Army and Air Force personnel were deployed to the base. The three who were killed and most of the wounded were Army soldiers, according to several U.S. officials, who spoke on condition of anonymity to give details not yet made public.

The small installation, which Jordan does not publicly disclose, includes U.S. engineering, aviation, logistics and security troops. Austin said the troops were deployed there “to work for the lasting defeat of ISIS.” Three officials said the drone struck near the troops’ sleeping quarters, which they said explained the high casualty count.

The U.S. military base at al-Tanf in Syria is just 20 kilometers (12 miles) north of Tower 22. The Jordanian installation provides a critical logistical hub for U.S. forces in Syria, including those at al-Tanf, which is near where the borders of Iraq, Syria and Jordan intersect.

In a statement on Jordan’s state-run Petra news agency, the country “condemned the terrorist attack” that targeted the U.S. troops. That report described the drone strike as targeting “an outpost on the border with Syria” and said it did not wound any Jordanian troops.

“Jordan will continue to counter terrorism and the smuggling of drugs and weapons across the Syrian border into Jordan, and will confront with firmness and determination anyone who attempts to attack the security of the kingdom,” the statement attributed to Muhannad Mubaidin, a government spokesman, said.

U.S. troops long have used Jordan, a kingdom bordering Iraq, Israel, the Palestinian territory of the West Bank, Saudi Arabia and Syria, as a basing point. Some 3,000 American troops typically are stationed across Jordan.

Since the war in Gaza began Oct. 7, Iranian-backed militias have struck American military installations in Iraq more than 60 times and in Syria more than 90 times, with a mix of drones, rockets, mortars and ballistic missiles. The attack Sunday was the first targeting American troops in Jordan during the Israel-Hamas war and the first to result in the loss of American lives. Scores of U.S. personnel have been wounded, including some with traumatic brain injuries, during the attacks.

The militias have said that their strikes are in retaliation for Washington’s support for Israel in the war in Gaza and that they aim to push U.S. forces out of the region.

On Monday, Iran’s foreign ministry dismissed the U.S. accusation that Tehran was behind the drone strike,” according to the official IRNA news agency. It quoted ministry spokesman Nasser Kanaani as saying that the “Islamic Republic of Iran has no role in decisions by resistance groups on how they support the Palestinian nation or defend their people.”

Iran, Kanaani said, is closely watching developments in the region and stressed that the “responsibility for the consequences of provocative accusations against Iran will be on those who raise the baseless allegations.”

The U.S. in recent months has struck targets in Iraq, Syria and Yemen to respond to attacks on American forces in the region and to deter Iran-backed Houthi rebels from continuing to threaten commercial shipping in the Red Sea.

“I am confident the Biden Administration will respond in a deliberate and proportional manner,” said Sen. Jack Reed, D-R.I., who heads the Senate Armed Services Committee.

Republicans in Congress said the administration’s approach had failed to deter America’s adversaries in the region.

“We need a major reset of our Middle East policy to protect our national security interests,” said Republican Rep. Michael McCaul of Texas, chairman of the House Foreign Affairs Committee. Sen. Lindsay Graham, R-S.C., went further, urging the administration “to strike targets of significance inside Iran, not only as reprisal for the killing of our forces, but as deterrence against future aggression. The only thing the Iranian regime understands is force.”

Biden, who was in Columbia, South Carolina, on Sunday, was briefed in the morning by Austin, national security adviser Jake Sullivan, and principal deputy national security adviser Jon Finer, White House press secretary Karine Jean-Pierre said. In the afternoon, he met virtually with Vice President Kamala Harris and his national security team for an update.

The president, in the written statement, called it a “despicable and wholly unjust attack” and said the service members were “risking their own safety for the safety of their fellow Americans, and our allies and partners with whom we stand in the fight against terrorism. It is a fight we will not cease.”

Syria is still in the midst of a civil war and long has been a launch pad for Iranian-backed forces there, including the Lebanese militia Hezbollah. Iraq has multiple Iranian-backed Shiite militias operating there as well.

Jordan, a staunch Western ally and a crucial power in Jerusalem for its oversight of holy sites there, is suspected of launching airstrikes in Syria to disrupt drug smugglers, including one that killed nine people earlier this month.

An umbrella group for Iran-backed factions known as the Islamic Resistance in Iraq earlier claimed launching explosive drone attacks targeting three areas in Syria, as well as one inside of “occupied Palestine.” The group has claimed responsibility for dozens of attacks against bases housing U.S. troops in Iraq and Syria since the Israel-Hamas war began.

Three officials with Iran-backed militias in Iraq, who spoke on condition of anonymity because they were not authorized to discuss the matter with journalists, said the drone attack against the base in Jordan was launched by one of the Iraqi groups. No faction has yet officially claimed responsibility.

Officials said the U.S. military is not tracking any other attacks on its forces Sunday in the region.

___

Associated Press writers Zeke Miller and Lolita C. Baldor reported from Washington; Nasser Karimi in Tehran, Iran; Bassem Mroue and Abby Sewell in Beirut; Qassim Abdul-Zahra in Baghdad; Omar Akour in Amman, Jordan, and Jon Gambrell in Jerusalem contributed to this report.

The Iran-backed militant group blamed Israel for the deadly explosions, which targeted an extraordinary breadth of people and showed signs of being a long-planned operation. How the attack was executed is largely uncertain and investigators have not immediately said how the pagers were detonated. The Israeli military has declined to comment.

Here’s what we know so far.

Why were pagers used in the attack?

Hezbollah leader Hassan Nasrallah previously warned the group’s members not to carry cellphones, saying they could be used by Israel to track the group’s movements. As a result, the organization uses pagers to communicate.

A Hezbollah official told The Associated Press the exploded devices were from a new brand the group had not used before. The official, who spoke on condition of anonymity because he was not authorized to talk to the press, did not identify the brand name or supplier.

Nicholas Reese, adjunct instructor at the Center for Global Affairs in New York University’s School of Professional Studies, explains smart phones carry a higher risk for intercepted communications in contrast to the more simple technology of pagers.

This type of attack will also force Hezbollah to change their communication strategies, said Reese, who previously worked as an intelligence officer, adding that survivors of Tuesday’s explosions are likely to throw away “not just their pagers, but their phones, and leaving their tablets or any other electronic devices.”

How could sabotage cause these pagers to explode?

With little disclosed from investigators so far, multiple theories have emerged Tuesday around how the attack might have been carried out. Several experts who spoke with The Associated Press suggest that the explosions were most likely the result of supply-chain interference.

Very small explosive devices may have been built into the pagers prior to their delivery to Hezbollah, and then all remotely triggered simultaneously, possibly with a radio signal.

By the time of the attack, “the battery was probably half-explosive and half-actual battery,” said Carlos Perez, director of security intelligence at TrustedSec.

A former British Army bomb disposal officer explained that an explosive device has five main components: A container, a battery, a triggering device, a detonator and an explosive charge.

“A pager has three of those already,” explained the ex-officer, who spoke on condition of anonymity because he now works as a consultant with clients on the Middle East. “You would only need to add the detonator and the charge.”

After security camera footage appeared on social media Tuesday purporting to show one of the pagers explode on a man’s hip in a Lebanese market, two munitions experts also said that the blast appeared to be the result of a tiny explosive device.

“Looking at the video, the size of the detonation is similar to that caused by an electric detonator alone or one that incorporates an extremely small, high-explosive charge,” said Sean Moorhouse, a former British Army officer and explosive ordinance disposal expert.

This signals involvement of a state actor, Moorhouse said. He adds that Israel’s foreign intelligence agency, the Mossad, is the most obvious suspect to have the resources to carry out such an attack.

N.R. Jenzen-Jones, an expert in military arms who is director of the Australian-based Armament Research Services, agreed that the scale and sophistication of the attack “almost certainly points to a state actor,” and that Israel had been accused of carrying out such operations in the past. Last year, AP reported that Iran accused Israel of trying to sabotage its ballistic missile program through faulty foreign parts that could explode, damaging or destroying the weapons before they could be used.

How long was this operation?

It would take a long time to plan an attack of this scale. The exact specifics are still unknown, but experts who spoke with the AP shared estimates ranging anywhere between several months to two years.

The sophistication of the attack suggests that whoever is behind it has been collecting intelligence for a long time, Reese explained. An attack of this caliber requires building the relationships needed to gain physical access to the pagers before they were sold; developing the technology that would be embedded in the devices; and developing sources who can confirm that the targets were carrying the pagers.

And it’s likely the compromised pagers seemed normal to their users for some time before the attack. Elijah J. Magnier, a Brussels-based veteran and a senior political risk analyst with over 37 years experience in the region, said he has had conversations with members of Hezbollah and survivors of Tuesday’s pager attack. He said the pagers were procured more than six months ago.

“The pagers functioned perfectly for six months,” Magnier said. What triggered the explosion, he said, appeared to be an error message sent to all the devices.

Based on his conversations with Hezbollah members, Magnier also said that many pagers didn’t go off, allowing the group to inspect them. They came to the conclusion that between 3 to 5 grams of a highly explosive material were concealed or embedded in the circuitry, he said.

What else could have happened?

Another possibility is that malware could have been inserted into the operating system of the pagers — somehow causing the device batteries to all overload at a specific time, causing them to burst into flame.

According to a Hezbollah official and Lebanese security officials, the pagers first heated up and then exploded in the pockets, or the hands, of those carrying them Tuesday afternoon.

These pagers run on lithium ion batteries, the Hezboolah official said, claiming the devices exploded as the result of being targeted from an Israeli “security operation,” without elaborating further.

When overheated, lithium ion batteries can smoke, melt and even catch on fire. Rechargeable lithium batteries are used in consumer products ranging from cellphones and laptops to electric cars. Lithium battery fires can burn up to 590 C (1,100 F).

Still, Moorhouse and others noted that images and video footage seen Tuesday more strongly resembled the detonation of small explosive charge, not an overheating battery.

“A lithium ion battery fire is one thing, but I’ve never seen one explode like that. It looks like a small explosive charge,” said Alex Plitsas, a weapons expert at the Atlantic Council.

Among those pointing to the likelihood of a supply chain attack is Jenzen-Jones, who adds that “such a large-scale operation also raises questions of targeting” — stressing the number of causalities and enormous impact reported so far.

“How can the party initiating the explosive be sure that a target’s child, for example, is not playing with the pager at the time it functions?” he said.

The Iran-backed militant group blamed Israel for the deadly explosions, which targeted an extraordinary breadth of people and showed signs of being a long-planned operation. How the attack was executed is largely uncertain and investigators have not immediately said how the pagers were detonated. The Israeli military has declined to comment.

Here’s what we know so far.

Why were pagers used in the attack?

Hezbollah leader Hassan Nasrallah previously warned the group’s members not to carry cellphones, saying they could be used by Israel to track the group’s movements. As a result, the organization uses pagers to communicate.

A Hezbollah official told The Associated Press the exploded devices were from a new brand the group had not used before. The official, who spoke on condition of anonymity because he was not authorized to talk to the press, did not identify the brand name or supplier.

Nicholas Reese, adjunct instructor at the Center for Global Affairs in New York University’s School of Professional Studies, explains smart phones carry a higher risk for intercepted communications in contrast to the more simple technology of pagers.

This type of attack will also force Hezbollah to change their communication strategies, said Reese, who previously worked as an intelligence officer, adding that survivors of Tuesday’s explosions are likely to throw away “not just their pagers, but their phones, and leaving their tablets or any other electronic devices.”

How could sabotage cause these pagers to explode?

With little disclosed from investigators so far, multiple theories have emerged Tuesday around how the attack might have been carried out. Several experts who spoke with The Associated Press suggest that the explosions were most likely the result of supply-chain interference.

Very small explosive devices may have been built into the pagers prior to their delivery to Hezbollah, and then all remotely triggered simultaneously, possibly with a radio signal.

By the time of the attack, “the battery was probably half-explosive and half-actual battery,” said Carlos Perez, director of security intelligence at TrustedSec.

A former British Army bomb disposal officer explained that an explosive device has five main components: A container, a battery, a triggering device, a detonator and an explosive charge.

“A pager has three of those already,” explained the ex-officer, who spoke on condition of anonymity because he now works as a consultant with clients on the Middle East. “You would only need to add the detonator and the charge.”

After security camera footage appeared on social media Tuesday purporting to show one of the pagers explode on a man’s hip in a Lebanese market, two munitions experts also said that the blast appeared to be the result of a tiny explosive device.

“Looking at the video, the size of the detonation is similar to that caused by an electric detonator alone or one that incorporates an extremely small, high-explosive charge,” said Sean Moorhouse, a former British Army officer and explosive ordinance disposal expert.

This signals involvement of a state actor, Moorhouse said. He adds that Israel’s foreign intelligence agency, the Mossad, is the most obvious suspect to have the resources to carry out such an attack.

N.R. Jenzen-Jones, an expert in military arms who is director of the Australian-based Armament Research Services, agreed that the scale and sophistication of the attack “almost certainly points to a state actor,” and that Israel had been accused of carrying out such operations in the past. Last year, AP reported that Iran accused Israel of trying to sabotage its ballistic missile program through faulty foreign parts that could explode, damaging or destroying the weapons before they could be used.

How long was this operation?

It would take a long time to plan an attack of this scale. The exact specifics are still unknown, but experts who spoke with the AP shared estimates ranging anywhere between several months to two years.

The sophistication of the attack suggests that whoever is behind it has been collecting intelligence for a long time, Reese explained. An attack of this caliber requires building the relationships needed to gain physical access to the pagers before they were sold; developing the technology that would be embedded in the devices; and developing sources who can confirm that the targets were carrying the pagers.

And it’s likely the compromised pagers seemed normal to their users for some time before the attack. Elijah J. Magnier, a Brussels-based veteran and a senior political risk analyst with over 37 years experience in the region, said he has had conversations with members of Hezbollah and survivors of Tuesday’s pager attack. He said the pagers were procured more than six months ago.

“The pagers functioned perfectly for six months,” Magnier said. What triggered the explosion, he said, appeared to be an error message sent to all the devices.

Based on his conversations with Hezbollah members, Magnier also said that many pagers didn’t go off, allowing the group to inspect them. They came to the conclusion that between 3 to 5 grams of a highly explosive material were concealed or embedded in the circuitry, he said.

What else could have happened?

Another possibility is that malware could have been inserted into the operating system of the pagers — somehow causing the device batteries to all overload at a specific time, causing them to burst into flame.

According to a Hezbollah official and Lebanese security officials, the pagers first heated up and then exploded in the pockets, or the hands, of those carrying them Tuesday afternoon.

These pagers run on lithium ion batteries, the Hezboolah official said, claiming the devices exploded as the result of being targeted from an Israeli “security operation,” without elaborating further.

When overheated, lithium ion batteries can smoke, melt and even catch on fire. Rechargeable lithium batteries are used in consumer products ranging from cellphones and laptops to electric cars. Lithium battery fires can burn up to 590 C (1,100 F).

Still, Moorhouse and others noted that images and video footage seen Tuesday more strongly resembled the detonation of small explosive charge, not an overheating battery.

“A lithium ion battery fire is one thing, but I’ve never seen one explode like that. It looks like a small explosive charge,” said Alex Plitsas, a weapons expert at the Atlantic Council.

Among those pointing to the likelihood of a supply chain attack is Jenzen-Jones, who adds that “such a large-scale operation also raises questions of targeting” — stressing the number of causalities and enormous impact reported so far.

“How can the party initiating the explosive be sure that a target’s child, for example, is not playing with the pager at the time it functions?” he said.

Even as the U.S. and allies pummeled more than two dozen Iran-backed Houthi locations on Friday in retaliation for attacks on ships, the Houthis have continued their maritime assaults. And Tehran struck sites in Iraq and Syria, claiming to target an Israeli “spy headquarters,” then followed that Tuesday with reported missile and drone attacks in Pakistan.

The chaotic wave of attacks and reprisals involving the United States, its allies and foes suggested not only that last week’s assault had failed to deter the Houthis, but that the broader regional war that the U.S. has spent months trying to avoid was becoming closer to reality. And underscoring the gravity of the roiling situation, the Biden administration is expected to announce plans to redesignate the Houthis as global terrorists, according to people familiar with the decision who requested anonymity to discuss the matter ahead of its announcement.

At the White House earlier Tuesday, National Security Council spokesman John Kirby stressed that the U.S. is “not looking for a war. We’re not looking to expand this. The Houthis have a choice to make.” But in a speech at the World Economic Forum in Davos, Switzerland, White House national security adviser Jake Sullivan warned that the expanding array of attacks mean that allies must “be vigilant against the possibility that in fact, rather than heading towards de-escalation, we are on a path of escalation that we have to manage.”

Ever since the devastating attack by Hamas on Israel on Oct. 7 triggered a massive air and ground campaign by Israeli forces, the U.S. and other allies have worried about it expanding to a broader regional war. U.S. diplomatic and military officials have shuttled urgently across the Middle East, working to ease tensions but the enormous Palestinian death toll has fueled anger and is being touted as a reason for at least some of the attacks.

Since November, the Houthis have repeatedly targeted ships in the Red Sea, saying they were avenging Israel’s offensive against Hamas. But they have frequently targeted vessels with tenuous or no clear links to Israel, imperiling shipping in a key route for global trade.

In rapid succession in recent days, the Houthis fired an anti-ship cruise missile toward a U.S. Navy destroyer over the weekend, but the ship shot it down. The Houthis then struck a U.S.-owned ship in the Gulf of Aden on Monday and a Malta-flagged bulk carrier in the Red Sea on Tuesday. The attacks came despite the bombardment by U.S. and British ships and fighter jets of more than 60 Houthi targets in 28 locations on Friday.

Although the U.S. said that the subsequent Houthi maritime attacks have been smaller, and not as complex as earlier ones, it does appear that the militant group has not been deterred. And Iran’s Supreme Leader Ayatollah Ali Khamenei has praised the group’s actions.

According to U.S. Central Command, the U.S. launched a new strike against the Houthis on Tuesday, hitting four anti-ship ballistic missiles that were prepared to launch and presented an imminent threat to merchant and U.S. Navy ships in the region. Hours later, the Houthis claimed responsibility for the attack on the Malta-flagged bulk carrier Zografia. The ship was hit, but no one was injured and it continued on its way.

The attack Monday on the U.S.-owned Gibraltar Eagle also resulted in damage but no injuries, and it too continued on its journey.

The Houthis’ military spokesman, Brig. Gen. Yahya Saree, said in a pre-recorded statement that it fired at the Zografia after the ship’s crew refused to answer warning calls and that the vessel was heading for a port in Israel. According to the shipping tracking website Vessel Finder, Zografia was bound for Suez, Egypt.

While Iran arms and backs the Houthis, it’s not been clear how much it has helped plan or direct the attacks. But, Tehran launched its own assault on Israel’s interests late Monday, firing missiles near the U.S. Consulate in northern Iraq at what it said was a headquarters of Mossad, the Israeli intelligence agency,

Four civilians were killed and six injured in the strike in Irbil, the seat of Iraq’s semi-autonomous Kurdish region, according to the security council of the Kurdish regional government. Iran’s Revolutionary Guards said in a statement that it also fired a number of ballistic missiles at “terrorist operations,” including Islamic State targets, in Syria and destroyed them.

And on Tuesday, Iran struck targets inside Pakistan killing two “innocent children” and wounded three other people, the Pakistani government said. Iran described the targets as bases for the militant group Jaish al-Adl, state media reported.

Jaish al-Adl, or the “Army of Justice,” is a Sunni militant group which largely operates across the border in Pakistan. Iran has fought the militants in border areas, but a missile-and-drone attack on nuclear-armed Pakistan would be unprecedented for Iran.

Amid the latest attacks, U.S. Navy SEALs seized Iranian-made missile parts and other weaponry from a ship bound for Yemen’s Houthi rebels in a raid last week that saw two of its commandos go missing, the U.S. military said Tuesday. The raid marks the latest seizure by the U.S. Navy and its allies of weapon shipments bound for the rebels.

As they were boarding the ship in rough seas, one SEAL got knocked off by high waves and a teammate went in after him. Both remain missing.

The U.S. Navy ultimately sank the ship carrying the weapons and detained the 14 crew members. The Houthis have not acknowledged the seizure, and Iran’s mission to the United Nations did not respond to a request for comment. A United Nations resolution bans arms transfers to Yemen’s Iranian-backed Houthi rebels. Tehran has long denied arming the rebels, despite physical evidence, numerous seizures and experts tying the weapons back to Iran.

Associated Press writers Elena Becatoros in Athens, Greece, and Tara Copp and Aamer Madhani in Washington contributed to this report. Gambrell reported from Jerusalem.

The Iran-backed militant group blamed Israel for the deadly explosions, which targeted an extraordinary breadth of people and showed signs of being a long-planned operation. How the attack was executed is largely uncertain and investigators have not immediately said how the pagers were detonated. The Israeli military has declined to comment.

Here’s what we know so far.

Why were pagers used in the attack?

Hezbollah leader Hassan Nasrallah previously warned the group’s members not to carry cellphones, saying they could be used by Israel to track the group’s movements. As a result, the organization uses pagers to communicate.

A Hezbollah official told The Associated Press the exploded devices were from a new brand the group had not used before. The official, who spoke on condition of anonymity because he was not authorized to talk to the press, did not identify the brand name or supplier.

Nicholas Reese, adjunct instructor at the Center for Global Affairs in New York University’s School of Professional Studies, explains smart phones carry a higher risk for intercepted communications in contrast to the more simple technology of pagers.

This type of attack will also force Hezbollah to change their communication strategies, said Reese, who previously worked as an intelligence officer, adding that survivors of Tuesday’s explosions are likely to throw away “not just their pagers, but their phones, and leaving their tablets or any other electronic devices.”

How could sabotage cause these pagers to explode?

With little disclosed from investigators so far, multiple theories have emerged Tuesday around how the attack might have been carried out. Several experts who spoke with The Associated Press suggest that the explosions were most likely the result of supply-chain interference.

Very small explosive devices may have been built into the pagers prior to their delivery to Hezbollah, and then all remotely triggered simultaneously, possibly with a radio signal.

By the time of the attack, “the battery was probably half-explosive and half-actual battery,” said Carlos Perez, director of security intelligence at TrustedSec.

A former British Army bomb disposal officer explained that an explosive device has five main components: A container, a battery, a triggering device, a detonator and an explosive charge.

“A pager has three of those already,” explained the ex-officer, who spoke on condition of anonymity because he now works as a consultant with clients on the Middle East. “You would only need to add the detonator and the charge.”

After security camera footage appeared on social media Tuesday purporting to show one of the pagers explode on a man’s hip in a Lebanese market, two munitions experts also said that the blast appeared to be the result of a tiny explosive device.

“Looking at the video, the size of the detonation is similar to that caused by an electric detonator alone or one that incorporates an extremely small, high-explosive charge,” said Sean Moorhouse, a former British Army officer and explosive ordinance disposal expert.

This signals involvement of a state actor, Moorhouse said. He adds that Israel’s foreign intelligence agency, the Mossad, is the most obvious suspect to have the resources to carry out such an attack.

N.R. Jenzen-Jones, an expert in military arms who is director of the Australian-based Armament Research Services, agreed that the scale and sophistication of the attack “almost certainly points to a state actor,” and that Israel had been accused of carrying out such operations in the past. Last year, AP reported that Iran accused Israel of trying to sabotage its ballistic missile program through faulty foreign parts that could explode, damaging or destroying the weapons before they could be used.

How long was this operation?

It would take a long time to plan an attack of this scale. The exact specifics are still unknown, but experts who spoke with the AP shared estimates ranging anywhere between several months to two years.

The sophistication of the attack suggests that whoever is behind it has been collecting intelligence for a long time, Reese explained. An attack of this caliber requires building the relationships needed to gain physical access to the pagers before they were sold; developing the technology that would be embedded in the devices; and developing sources who can confirm that the targets were carrying the pagers.

And it’s likely the compromised pagers seemed normal to their users for some time before the attack. Elijah J. Magnier, a Brussels-based veteran and a senior political risk analyst with over 37 years experience in the region, said he has had conversations with members of Hezbollah and survivors of Tuesday’s pager attack. He said the pagers were procured more than six months ago.

“The pagers functioned perfectly for six months,” Magnier said. What triggered the explosion, he said, appeared to be an error message sent to all the devices.

Based on his conversations with Hezbollah members, Magnier also said that many pagers didn’t go off, allowing the group to inspect them. They came to the conclusion that between 3 to 5 grams of a highly explosive material were concealed or embedded in the circuitry, he said.

What else could have happened?

Another possibility is that malware could have been inserted into the operating system of the pagers — somehow causing the device batteries to all overload at a specific time, causing them to burst into flame.

According to a Hezbollah official and Lebanese security officials, the pagers first heated up and then exploded in the pockets, or the hands, of those carrying them Tuesday afternoon.

These pagers run on lithium ion batteries, the Hezboolah official said, claiming the devices exploded as the result of being targeted from an Israeli “security operation,” without elaborating further.

When overheated, lithium ion batteries can smoke, melt and even catch on fire. Rechargeable lithium batteries are used in consumer products ranging from cellphones and laptops to electric cars. Lithium battery fires can burn up to 590 C (1,100 F).

Still, Moorhouse and others noted that images and video footage seen Tuesday more strongly resembled the detonation of small explosive charge, not an overheating battery.

“A lithium ion battery fire is one thing, but I’ve never seen one explode like that. It looks like a small explosive charge,” said Alex Plitsas, a weapons expert at the Atlantic Council.

Among those pointing to the likelihood of a supply chain attack is Jenzen-Jones, who adds that “such a large-scale operation also raises questions of targeting” — stressing the number of causalities and enormous impact reported so far.

“How can the party initiating the explosive be sure that a target’s child, for example, is not playing with the pager at the time it functions?” he said.

The Iran-backed militant group blamed Israel for the deadly explosions, which targeted an extraordinary breadth of people and showed signs of being a long-planned operation. How the attack was executed is largely uncertain and investigators have not immediately said how the pagers were detonated. The Israeli military has declined to comment.

Here’s what we know so far.

Why were pagers used in the attack?

Hezbollah leader Hassan Nasrallah previously warned the group’s members not to carry cellphones, saying they could be used by Israel to track the group’s movements. As a result, the organization uses pagers to communicate.

A Hezbollah official told The Associated Press the exploded devices were from a new brand the group had not used before. The official, who spoke on condition of anonymity because he was not authorized to talk to the press, did not identify the brand name or supplier.

Nicholas Reese, adjunct instructor at the Center for Global Affairs in New York University’s School of Professional Studies, explains smart phones carry a higher risk for intercepted communications in contrast to the more simple technology of pagers.

This type of attack will also force Hezbollah to change their communication strategies, said Reese, who previously worked as an intelligence officer, adding that survivors of Tuesday’s explosions are likely to throw away “not just their pagers, but their phones, and leaving their tablets or any other electronic devices.”

How could sabotage cause these pagers to explode?

With little disclosed from investigators so far, multiple theories have emerged Tuesday around how the attack might have been carried out. Several experts who spoke with The Associated Press suggest that the explosions were most likely the result of supply-chain interference.

Very small explosive devices may have been built into the pagers prior to their delivery to Hezbollah, and then all remotely triggered simultaneously, possibly with a radio signal.

By the time of the attack, “the battery was probably half-explosive and half-actual battery,” said Carlos Perez, director of security intelligence at TrustedSec.

A former British Army bomb disposal officer explained that an explosive device has five main components: A container, a battery, a triggering device, a detonator and an explosive charge.

“A pager has three of those already,” explained the ex-officer, who spoke on condition of anonymity because he now works as a consultant with clients on the Middle East. “You would only need to add the detonator and the charge.”

After security camera footage appeared on social media Tuesday purporting to show one of the pagers explode on a man’s hip in a Lebanese market, two munitions experts also said that the blast appeared to be the result of a tiny explosive device.

“Looking at the video, the size of the detonation is similar to that caused by an electric detonator alone or one that incorporates an extremely small, high-explosive charge,” said Sean Moorhouse, a former British Army officer and explosive ordinance disposal expert.

This signals involvement of a state actor, Moorhouse said. He adds that Israel’s foreign intelligence agency, the Mossad, is the most obvious suspect to have the resources to carry out such an attack.

N.R. Jenzen-Jones, an expert in military arms who is director of the Australian-based Armament Research Services, agreed that the scale and sophistication of the attack “almost certainly points to a state actor,” and that Israel had been accused of carrying out such operations in the past. Last year, AP reported that Iran accused Israel of trying to sabotage its ballistic missile program through faulty foreign parts that could explode, damaging or destroying the weapons before they could be used.

How long was this operation?

It would take a long time to plan an attack of this scale. The exact specifics are still unknown, but experts who spoke with the AP shared estimates ranging anywhere between several months to two years.

The sophistication of the attack suggests that whoever is behind it has been collecting intelligence for a long time, Reese explained. An attack of this caliber requires building the relationships needed to gain physical access to the pagers before they were sold; developing the technology that would be embedded in the devices; and developing sources who can confirm that the targets were carrying the pagers.

And it’s likely the compromised pagers seemed normal to their users for some time before the attack. Elijah J. Magnier, a Brussels-based veteran and a senior political risk analyst with over 37 years experience in the region, said he has had conversations with members of Hezbollah and survivors of Tuesday’s pager attack. He said the pagers were procured more than six months ago.

“The pagers functioned perfectly for six months,” Magnier said. What triggered the explosion, he said, appeared to be an error message sent to all the devices.

Based on his conversations with Hezbollah members, Magnier also said that many pagers didn’t go off, allowing the group to inspect them. They came to the conclusion that between 3 to 5 grams of a highly explosive material were concealed or embedded in the circuitry, he said.

What else could have happened?

Another possibility is that malware could have been inserted into the operating system of the pagers — somehow causing the device batteries to all overload at a specific time, causing them to burst into flame.

According to a Hezbollah official and Lebanese security officials, the pagers first heated up and then exploded in the pockets, or the hands, of those carrying them Tuesday afternoon.

These pagers run on lithium ion batteries, the Hezboolah official said, claiming the devices exploded as the result of being targeted from an Israeli “security operation,” without elaborating further.

When overheated, lithium ion batteries can smoke, melt and even catch on fire. Rechargeable lithium batteries are used in consumer products ranging from cellphones and laptops to electric cars. Lithium battery fires can burn up to 590 C (1,100 F).

Still, Moorhouse and others noted that images and video footage seen Tuesday more strongly resembled the detonation of small explosive charge, not an overheating battery.

“A lithium ion battery fire is one thing, but I’ve never seen one explode like that. It looks like a small explosive charge,” said Alex Plitsas, a weapons expert at the Atlantic Council.

Among those pointing to the likelihood of a supply chain attack is Jenzen-Jones, who adds that “such a large-scale operation also raises questions of targeting” — stressing the number of causalities and enormous impact reported so far.

“How can the party initiating the explosive be sure that a target’s child, for example, is not playing with the pager at the time it functions?” he said.