Hezbollah's leader acknowledged Thursday that his group had suffered an "unprecedented" blow when thousands of operatives' communication devices exploded across Lebanon in deadly attacks it blamed on Israel.

In his first speech since the attacks, which killed 37 people and wounded nearly 3,000 across two days, Hassan Nasrallah struck a defiant tone, vowing that Israel would face retribution.

Even as he delivered his televised address, Israeli warplanes broke the sound barrier over Beirut.

Describing the attacks as a "massacre" and a possible "act of war", Nasrallah said Israel would face "tough retribution and just punishment, where it expects it and where it does not".

Israel has not commented on the attacks in which Hezbollah pagers and walkie-talkies exploded in supermarkets, on streets and at funerals, plunging the country into panic.

But Defence Minister Yoav Gallant said on Wednesday, in reference to Israel's border with Lebanon: "The centre of gravity is moving northward.

"We are at the start of a new phase in the war," he warned.

Iran-backed Hezbollah is an ally of Palestinian militant group Hamas, which has been fighting a war in Gaza since its October 7 attack on Israel.

For nearly a year, the focus of Israel's firepower has been on Gaza but its troops have also been engaged in near-daily clashes with Hezbollah militants along its northern border.

Hundreds have been killed in Lebanon, most of them fighters, and dozens in Israel, including soldiers.

The exchanges of fire have forced tens of thousands of people on both sides of the border to flee their homes.

Nasrallah vowed to keep up Hezbollah's fight against Israel until a ceasefire in Gaza is reached.

Hamas welcomed the promise of support.

Gallant vowed that Israel's military actions against Hezbollah "will continue".

"In the new phase of the war there are significant opportunities but also significant risks. Hezbollah feels persecuted," the minister said.

The Israeli military announced new strikes in Lebanon on Thursday which it said hit "hundreds of rocket launcher barrels" ready to be fired towards Israel as well as "approximately 100 launchers and additional terrorist infrastructure sites".

It said two soldiers were killed near the border.

- 'Wider war' -

 

Hezbollah said 25 of its members had been killed in the device explosions, with a source close to the group saying at least 20 had died when their walkie-talkies blew up.

Foreign Minister Abdallah Bou Habib said the "blatant assault on Lebanon's sovereignty and security" was a dangerous development that could "signal a wider war".

Speaking ahead of a UN Security Council meeting on the attacks set for Friday, he said Lebanon had filed a complaint against "Israel's cyber-terrorist aggression that amounts to a war crime".

Iran's Revolutionary Guards said Israel faces "a crushing response from the resistance front" after the blasts, which wounded Tehran's ambassador in Beirut.

US Secretary of State Antony Blinken, who has been scrambling to salvage efforts for a Gaza ceasefire and hostage release deal, called for restraint by all sides.

"We don't want to see any escalatory actions by any party" that would endanger the goal of a ceasefire in Gaza, he said as he joined European foreign ministers in Paris to discuss the widening crisis.

Press Secretary Karine Jean-Pierre said President Joe Biden still believes there can be a diplomatic solution between Israel and Hezbollah. "He believes it's achievable," she told a briefing.

Palestinian president Mahmud Abbas, in Madrid, called for a new peace conference aimed at ending the Israeli-Palestinian conflict.

Hamas's unprecedented October 7 attacks that sparked the Gaza war resulted in the deaths of 1,205 people, mostly civilians, on the Israeli side, according to an AFP tally based on Israeli official figures that include hostages killed in captivity.

Out of 251 hostages seized by militants, 97 are still held in Gaza, including 33 the Israeli military says are dead.

Israel's retaliatory military offensive has killed at least 41,272 people in Gaza, most of them civilians, according to figures provided by the Hamas-run territory's health ministry. The United Nations has acknowledged the figures as reliable.

In Lebanon, the influx of so many casualties following the blasts overwhelmed medics and triggered panic.

"What happened in the last two days is so frightening. It's terrifying," Lina Ismail told AFP by phone from the eastern city of Baalbek.

"I took away my daughter's power bank and we even sleep with our mobile phones in a separate room," she added in a trembling voice.

Qatar Airways announced that following a decision by Lebanese civil aviation authorities, all passengers flying from Beirut were "prohibited from carrying pagers and walkie-talkies on board flights".

- 'Sabotaged at source' -

 

The preliminary findings of a Lebanese investigation found the pagers had been booby-trapped, a security official said.

The country's mission to the United Nations concurred, saying in a letter that the probe showed "the targeted devices were professionally booby-trapped... before arriving in Lebanon, and were detonated by sending emails to the devices".

A source close to Hezbollah, asking not to be identified, said the pagers were recently imported and appeared to have been "sabotaged at source".

The New York Times reported Wednesday that the pagers that exploded were produced by the Hungary-based BAC Consulting on behalf of Taiwanese manufacturer Gold Apollo. It cited intelligence officers as saying BAC was part of an Israeli front.

A government spokesman in Budapest said the company was "a trading intermediary, with no manufacturing or operational site in Hungary".

Japanese firm Icom said it had stopped producing the model of radios reportedly used in Wednesday's blasts in Lebanon around 10 years ago.