At least 18 people have been killed in southern Lebanon following a series of Israeli air strikes overnight, the country's health ministry has said - while the Israeli military says four of its soldiers were also killed.
The Israel Defense Forces (IDF) said it had struck 80 targets linked to the Iran-backed armed group Hezbollah and killed "dozens" of its members.
It comes a day after the US and Iran signed a deal aimed at ending the conflict in the Middle East, including a permanent cessation of hostilities in Lebanon.
Both Israel and Hezbollah have carried out strikes against each other since the agreement was announced, raising questions about the future of the truce between the US and Iran.
The US-Iran deal calls for an end to hostilities on all fronts, and for Lebanon's territorial integrity and sovereignty to be respected.
However, Israel has said it has no intention of withdrawing its forces from Lebanon and has insisted that its conflict with Hezbollah is separate from the war on Iran.
Lebanon's state news agency described the overnight bombardment across the Nabatieh district of southern Lebanon on Thursday as one of the most intense of the war, with at least 18 killed, 33 injured and several buildings hit.
Hezbollah said it had ambushed an Israeli group in southern Lebanon, destroying three tanks with guided missiles, and targeting troops with rocket and artillery fire.
Israeli Prime Minister Benjamin Netanyahu extended his condolences to the four soldiers, writing on X on Friday that he had instructed the IDF to "strike Hezbollah with full force".
"My directive is clear: Israel will not tolerate attacks on our soldiers or our territory, and it will exact a very heavy price from Hezbollah for these attacks," he said.
Lebanese President Joseph Aoun said that the "expansion of Israeli attacks constitutes a dangerous and condemned escalation", adding that it would "not deter efforts to achieve a comprehensive ceasefire as quickly as possible".
Lebanon was drawn into the war between Israel, the US and Iran shortly after it began, with Hezbollah launching rockets into Israel in retaliation for a strike that killed Iran's supreme leader.
Israel responded by launching a bombing campaign across Lebanon and occupying around 5% of the country's territory in the south, with the aim of driving back Hezbollah fighters from its northern border.
At least 3,912 people have been killed, among them women and children, and a further 11,699 others wounded since the latest conflict began, according to Lebanon's health ministry.
Around a million people remain displaced, while dozens of communities in the south have been completely destroyed.
Hezbollah has vowed to continue with its attacks as long as the invasion persists.
Netanyahu is under domestic pressure to continue military operations against the armed group, which could put him on a collision course with US President Donald Trump, who has publicly criticised Israel's conduct in Lebanon.
Israel's far-right National Security Minister Itamar Ben-Gvir said that "all of Lebanon must burn" following the deaths of the four soldiers.
"With all due respect to the Americans, Israel must make it clear to the entire world that the blood of our sons and the security of our citizens are not up for bargaining," he said in a statement.
French Foreign Minister Jean-Noël Barrot said on Friday that Israel must "respect" the deal and urged the US to put pressure on the Israeli government.
The US-Iran agreement signed on Thursday includes provisions on Iran's nuclear programme, sanctions relief and commits both sides to pursuing a final settlement within 60 days, a deadline that can be extended by mutual agreement.
A new round of direct talks scheduled for Friday was delayed after US Vice-President JD Vance cancelled his planned trip to Switzerland to attend them.
Vance previously criticised the attitude of some members of Netanyahu's cabinet towards the deal, saying they should "wake up and smell reality".
"If I was in the cabinet of the Israeli government, I might not be attacking the only powerful ally that I have anywhere left in the entire world," he told reporters.
Vance named Ben-Gvir and Finance Minister Bezalel Smotrich as critics of the deal in an interview with the New York Times.
He said: "I guess my response to them would be - what is your exact proposal? You're a country of nine million people. You can't just kill your way out of solving every single national security problem that you have."
Netanyahu himself stressed the importance of maintaining Israel's close ties with the US on Thursday, saying Washington had stood "shoulder to shoulder" with the country during the war with Iran.
However, that relationship has become strained of late, with leaks suggesting Trump has on several occasions vented his frustration with Netanyahu during phone conversations between the two leaders.
US officials have previously said that, while Lebanon was covered by the ceasefire framework, the withdrawal of Israeli forces from Lebanese territory was not a condition of the deal and that Israel would retain the right to self-defence.
