Tuesday’s deadly explosions, which were concentrated in Hezbollah strongholds including suburbs in southern Beirut, came as Israeli leaders again warned against expanding operations against Hamas-allied Hezbollah across the Lebanese border. Israel had begun moving troops to the border on Wednesday as a precautionary measure, AP reported, citing an Israeli official.

Hezbollah blamed Israel for the mass attack, which it had been bombarding almost daily since the start of the Gaza war, and vowed revenge.

Touring the hospital on Wednesday, Abiad said many of the injured had suffered “serious eye injuries” while others had to have limbs amputated. It remains unclear how many of the victims are linked to the Shiite militant group.

To avoid overcrowding, the injured were taken to various hospitals in Lebanon, Abiad said, adding that Turkey, Iraq, Iran, Syria and Egypt had offered their help in treating the patients.

UN Human Rights Commissioner Volker Türk said on Wednesday that those responsible for the explosions were breaking the law and must be held accountable.

“Targeting thousands of people simultaneously, whether civilians or members of armed groups, without knowing who was in possession of the targeting devices … violates international human rights law,” he said.

Here’s what we know:

While Israel has so far refused to comment, an unnamed US official said Washington had been informed of the long-range attack on Tuesday.

A senior Lebanese security source told AP that Israel’s Mossad intelligence agency planted explosives in thousands of pagers imported from Hezbollah months before the deadly blasts.

The Iran-backed militant group uses these low-tech devices instead of cell phones to evade location tracking and wiretapping by Israel.

A Hezbollah official told AP that the exploding pagers were a new brand that the group had not used before, but he did not name the manufacturer.

According to the Washington Post, Hezbollah called Tuesday’s explosions its biggest security breach and asked its members to turn off their pagers shortly after the detonation.

The deaths and injuries caused by the explosions are another of Hezbollah’s casualties in the fight against Israel. The group has lost several high-ranking commanders in targeted attacks by the Israeli army in recent months.

• The Taiwanese company Gold Apollo

The exploding pagers were traced to Gold Apollo, a small Taiwanese manufacturer based in New Taipei City that specializes in wireless communications devices.

Although images circulated online showing the company’s name and trademark on the handheld devices that exploded on Tuesday, Gold Apollo immediately denied any involvement in their production.

In a statement released Wednesday, the company said the model linked to the deadly explosions – the AR-924 – was manufactured and sold by its Hungarian partner BAC Consulting KFT.

The AR-924 has a rechargeable lithium battery, is advertised as “rugged” on Gold Apollo’s website, and can receive texts of up to 100 characters.

“Under the cooperation agreement, we authorize BAC to use our trademark for product sales in certain regions, but the design and manufacture of the products are the sole responsibility of BAC,” the statement said.

In a press conference at the company’s headquarters on Wednesday, CEO Hsu Ching-kuang said Gold Apollo has a licensing agreement with Budapest-based BAC Consulting and began working with the company three years ago.

Taiwan’s Ministry of Economic Affairs said Gold Apollo exported 260,000 pagers from early 2022 to August 2024, mainly to Europe and North America. However, there are no records of direct exports of Gold Apollo pagers to Lebanon.

In a statement sent to journalists, the ministry said the pagers that exploded in Lebanon and Syria were made in Taiwan – contradicting Gold Apollo’s statement – and added that they were likely modified by third parties abroad, local media reported.

• Hungarian company BAC Consulting

Apart from an inaccessible website and an address in the Hungarian capital, little information about Gold Apollo’s business partner is available on the Internet.

According to the Hungarian company register Opten, BAC Consulting was founded in 2022.

Hsu told reporters that Gold Apollo’s main contact with BAC Consulting is an Austrian named “Tom,” who runs the Hungarian company’s office in Taiwan. But FRANCE 24 could find no trace of the company’s registration with the Ministry of Economy. There are signs that it is a shell company.

The Hungarian government said in a post on X Wednesday that BAC Consulting was a “trading agent with no production or operating facility in Hungary,” adding that the exploding pagers were never in the country.

• Explosives probably added later

In an interview with FRANCE 24 on Tuesday, cybersecurity expert Gérôme Billois said the most likely scenario for the large-scale attack was the placement of explosives in the pagers after they left the factory.

“Surely an intelligence agency was aware of this order of pagers and was able to intercept them after production … open the box very precisely, change the battery or put an explosive in the battery and then also change the software to enable this remote activation,” he said.

Although it would be difficult to intercept the pagers somewhere in the supply chain before they reach their final destination, Billois said the task was feasible because intelligence agencies had carried out similar operations in the past.

Another possibility would be to manipulate the lithium batteries so that they explode when a radio signal arrives, said Billois. However, he considers this scenario less likely.

Former US National Security Agency (NSA) intelligence analyst David Kennedy seems to agree. He told CNN that the explosions were too violent to have been caused by exploding batteries.

“The pagers would have been implanted with explosives and would probably only have detonated if a specific message was received,” CNN quoted him as saying.

According to the New York Times, the pagers were remotely activated using a switch built into the devices when turned on and when messages were received.