Militant group Hezbollah has vowed retaliation against Israel, amid growing confirmation it was behind the deadly detonation of pagers across Lebanon.

US media, including The New York Times and CNN, is reporting that Israel was responsible for the attack, which killed at least 11 people – including a child – and wounded 2750 others.

US officials said on Wednesday (AEST) the Biden administration had no prior knowledge of the blasts.

The US “was not aware of this operation and was not involved”, US State Department spokesperson Matthew Miller said, adding that the US was “still gathering information”. He didn’t confirm that Israel was behind the attack.

Axios reports the operation was approved earlier this week during security meetings with Israeli Prime Minister Benjamin Netanyahu, senior members of his cabinet and security service bosses.

It came a day after US envoy Amos Hochstein visited Israel and warned Netanyahu of the consequences of a major escalation of the conflict in Lebanon.

Neither the Israeli government nor its military has commented on the detonations.

The Chief of the General Staff, LTG Herzi Halevi, held a situational assessment this evening (Tuesday), with the participation of the General Staff Forum, focusing on readiness in both offense and defense in all arenas. pic.twitter.com/5mcVJh28Cg

— Israel Defense Forces (@IDF) September 17, 2024

But the NYT has a report detailing how Israel carried out the operation, hiding explosive material in a batch of Taiwanese-made pagers imported into Lebanon.

Citing US and other officials, the Times said Hezbollah had ordered the pagers from a Taiwanese company it had not previously used. The devices were tampered with before reaching Lebanon, with as little as 28 grams of explosive material implanted next to the battery in each.

A switch was also embedded that could be triggered remotely to detonate the explosives.

At 3.30pm Tuesday (Lebanon time), hundreds of pagers received a simple message that appeared to have come from the terror group’s Hezbollah’s leadership. Instead, it activated the explosives.

They blew up in southern Lebanon, the southern suburbs of Beirut known as Dahiyeh and the eastern Bekaa Valley – all Hezbollah strongholds.

Regional broadcasters carried CCTV footage showing what appeared to be a small handheld device next to a grocery store cashier exploding as one shopper paid. Another clip showed a blast appearing to knock out someone at a market fruit stand.

Many of those hurt included Hezbollah fighters who are the sons of top officials from the armed group, two security sources told Reuters. Among the dead was the son of a Hezbollah member of the Lebanese parliament, Ali Ammar, they said.

“This is not a security targeting of one, two or three people. This is a targeting of an entire nation,” senior Hezbollah official Hussein Khalil said while paying his condolences for Ammar’s son.

Lebanese broadcaster Al Jadeed cited Ammar as saying what happened was an Israeli aggression.

“We will deal with the enemy in the language it understands,” he said.

Lebanese Information Minister Ziad Makary has condemned the detonations as an “Israeli aggression”, while Hezbollah said Israel would receive “its fair punishment”.

The Iranian ambassador to Lebanon, Mojtaba Amani, suffered a “superficial injury” and was under observation in hospital, Iran’s Fars news agency said.

After Tuesday’s blasts, Reuters journalists described scenes of widespread panic on the streets, and dozens of injured screaming in pain in hospitals.

One witness, who spoke to CNN outside the American University of Beirut Medical Centre and asked not to be named citing fears for his safety, described going outside in a southern Beirut suburb in the immediate aftermath.

“We went out to the streets, and we found the suburb as if it was a zombie city,” he said.

Injured people lay scattered on the roads, he said. Some of his friends were among the wounded.

Another witness, who also asked not to be named, said he was driving to work when he saw Red Cross ambulances and people lying on the ground.

“We were surprised that there were a lot of people … there was blood on the roads and people were being transported in ambulances to the hospital. But we did not know what was happening,” he said.

Hezbollah fighters use the pagers as a low-tech way to try to prevent Israel tracking their locations, two sources familiar with the group’s operations told Reuters earlier this year.

A Hezbollah official, speaking on condition of anonymity, said the detonation of the pagers was the group’s “biggest security breach” in nearly a year of conflict with Israel.

United Nations spokesman Stephane Dujarric said developments in Lebanon were extremely concerning, especially given the “extremely volatile” context, adding that the UN deplored any civilian casualties.

Without commenting directly on the explosions in Lebanon, an Israeli military spokesman said chief of staff Major General Herzi Halevi had met senior officers on Tuesday night to assess the situation.

No policy change was announced but “vigilance must continue to be maintained”, he said.

-with AAP