NEW YORK — In what appears to be a sophisticated, remote attack, pagers used by hundreds of members of miliant group Hezbollah exploded almost simultaneously in Lebanon and Syria Tuesday, killing at least 12 people — including two children — and wounding thousands more.

An American official said Israel briefed the U.S. on the operation — in which small amounts of explosive hidden in the pagers were detonated — on Tuesday after it was concluded. The person spoke on the condition of anonymity because they were not authorized to discuss the information publicly.

The Lebanese government and Iran-backed Hezbollah also blamed Israel for the deadly explosions, which targeted an extraordinary breadth of people and showed signs of being a long-planned operation. Details on how the attack was executed are 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.

Related Story: Wave of Exploding Pagers in Lebanon and Syria Kills at Least 8, Including ...

Why Pagers Were 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.

Pagers also run on a different wireless network than mobile phones, which makes them more resilient in times of emergency. And for a group like Hezbollah, the pagers provided a means to sidestep what’s believed to be intensive Israeli electronic surveillance on mobile phone networks in Lebanon.

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

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 now likely to throw away “not just their pagers, but their phones, and leaving their tablets or any other electronic devices.”

Related Story: With Hezbollah-Israel Conflict Contained, Iran’s Next Move May Be Modest

Origin of the Pagers

Taiwanese company Gold Apollo said Wednesday it had authorized use of its brand on the AR-924 pager model and a Budapest, Hungary-based company called BAC Consulting KFT produced and sold the pagers. BAC appears to be a shell company.

Gold Apollo’s chair, Hsu Ching-kuang, told journalists Wednesday that the firm has had a licensing agreement with BAC for the past three years. From the start of 2022 through August 2024, Gold Apollo has exported 260,000 sets of pagers — including more than 40,000 sets between January and August of this year, according to Taiwan’s Ministry of Economic Affairs. The ministry said that it had no records of direct exports of Gold Apollo pagers to Lebanon.

Elijah J. Magnier, a Brussels-based veteran and a senior political risk analyst who says he has had conversations with members of Hezbollah and survivors of Tuesday’s attack, notes that Hezbollah has been using pagers since the 2006 war with Israel.

The newer brand of pagers used in Tuesday’s explosions, he added, were procured more than six months ago. How they arrived in Lebanon remains unclear.

Related Story: Israel and Hezbollah Seemed on the Brink of War, Then Pulled Back. Here’s ...

How Sabotage Could Cause Pagers to Explode

Multiple theories emerged Tuesday around how the attack might have been carried out, but several experts who spoke with The Associated Press explained how 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, experts explained. That corroborates information shared from the U.S. official about small amounts of explosive being hidden in the pagers as part of an Israeli operation.

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,” said 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.”

Munitions experts also pointed to security camera footage that appeared on social media Tuesday, which purported to show one of the pagers exploding on a man’s hip in a Lebanese market.

“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. Israel has a long history of carrying out similar operations in the past.

Timeline of the 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 the culprit has been collecting intelligence for a long time, Reese said. 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.

Citing conversations with Hezbollah contacts, Magnier said what triggered Tuesday’s explosions appeared to be an error message that reached the devices and caused them to vibrate intensely — forcing users to reach the pager with both hands to click on buttons to stop them. This caused many users to injure both hands.

Introducing this error, Magnier explained, not only maximized the effectiveness of the blast — but also ensured that the user was “fully engaged with the device” when they tried to stop it.

Magnier said Hezbollah is currently investigating what type of explosives were used in the device, suspecting RDX or PETN, highly explosive materials even as much as 3-5 grams. They are also questioning whether the device had a GPS system allowing Israel to track movement of the group members.

N.R. Jenzen-Jones, an expert in military arms who is director of the Australian-based Armament Research Services, added 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.