Lebanon's Hezbollah reeling after second wave of deadly blasts

But its defence minister, Yoav Gallant, said on Wednesday, about 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 said.

Hezbollah is an ally of the 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, which is ruled by Hamas.

But its troops have also been engaged in near-daily clashes with Hezbollah militants along its northern border, killing hundreds in Lebanon, most of them fighters, and dozens in Israel.

In the latest cross-border fire, the Israeli military said it struck six Hezbollah "infrastructure sites" and a weapons storage facility in southern Lebanon overnight.

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

Rattled by the attacks that targeted its communication system, Iran-backed militant group Hezbollah said Israel was "fully responsible for this criminal aggression" and vowed revenge.

Hezbollah on Thursday said 20 of its members had been killed, with a source close to the group saying they had died when their walkie-talkies exploded a day earlier.

Hezbollah leader Hassan Nasrallah is scheduled to deliver an unscheduled televised speech later Thursday. His remarks will be closely monitored for any indication of how the group plans to respond to the attacks.

'Wider war'

Lebanese 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".

Iran's envoy to the UN said the country "reserves the right to take retaliatory measures" after its ambassador in Beirut was wounded in the blasts.

The White House, which is pressing to salvage efforts for an elusive ceasefire deal to end the Gaza war, warned all sides against "an escalation of any kind".

"We don't believe that the way to solve where we're at in this crisis is by additional military operations at all," said US National Security Council spokesman John Kirby.

The 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 official Israeli 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 data provided by the Hamas-run territory's health ministry. The UN has acknowledged these figures as reliable.

In Gaza on Wednesday, the civil defence agency said an Israeli strike on a school-turned-shelter killed five people, while the Israeli military said it targeted Hamas militants.

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

At a Beirut hospital, doctor Joelle Khadra said "The injuries were mainly to the eyes and hands, with finger amputations, shrapnel in the eyes -- some people lost their sight."

A doctor at another hospital in the Lebanese capital said he had worked through the night and that the injuries were "out of this world -- never seen anything like it".

'Sabotaged at source'

Analysts said operatives had likely planted explosives on the pagers before they were delivered to Hezbollah.