Lebanon's Hezbollah militant group said on Friday it was moving to a new and escalating phase in its war against Israel while Iran said "the spirit of resistance will be strengthened" after the killing of Hamas leader Yahya Sinwar.

Sinwar, a mastermind of the Oct. 7, 2023, attack that triggered the Gaza war, was killed during an operation by Israeli soldiers in the Palestinian enclave on Wednesday, a pivotal event in the year-long conflict, Reuters reported.

Western leaders said his death offered an opportunity for the conflict to end, but Israeli Prime Minister Benjamin Netanyahu said the war would go on until the hostages seized by Hamas militants were returned.

"Today we have settled the score. Today evil has been dealt a blow but our task has still not been completed," Netanyahu said in a recorded video statement after the death was confirmed on Thursday.

"To the dear hostage families, I say: This is an important moment in the war. We will continue full force until all your loved ones, our loved ones, are home."

Sinwar, who was named as Hamas' overall leader following the assassination of political chief Ismail Haniyeh in Tehran in July, was believed to have been hiding in the warren of tunnels Hamas has built under Gaza over the past two decades.

He was killed during a gun battle in southern Gaza on Wednesday by Israeli troops who were initially unaware that they had caught their country's number one enemy, Israeli officials said.

The military released drone video of what it said was Sinwar, sitting on an armchair and covered in dust inside a destroyed building.

Hamas has not made any comment itself, but sources within the group have said the indications they have seen suggest Sinwar was indeed killed by Israeli troops.

'CHIEF OBSTACLE'

Despite Western hopes of a ceasefire, Sinwar's death could dial up hostilities in the Middle East where the prospect of an even wider conflict has grown.

Israel has launched a ground campaign in Lebanon over the past month and is now planning a response to an Oct. 1 missile attack carried out by Iran, ally of Hamas and Lebanon's Hezbollah.

But the demise of the man who planned the attack last year in which fighters killed 1,200 people in Israel and captured more than 250 hostages, according to Israeli tallies, could also help push forward stalled efforts to end the war in which Israel has killed more than 42,000 Palestinians, according to Gaza health authorities.

U.S. President Joe Biden, who spoke to Netanyahu by phone to congratulate him, said Sinwar's death provided a chance for the conflict in Gaza to finally end and for Israeli hostages to be brought home.

The U.S. wants to kick-start talks on a proposal to achieve a ceasefire and secure the release of hostages, U.S. State Department spokesperson Matthew Miller said, calling Sinwar the "chief obstacle" to ending the war.

"That obstacle has obviously been removed. Can’t predict that that means whoever replaces (Sinwar) will agree to a ceasefire, but it does remove what has been in recent months the chief obstacle to getting one," he said. In recent weeks, Sinwar had refused to negotiate at all, Miller said.

Iran indicated no sign the killing would shift its support. "The spirit of resistance will be strengthened" following the death of Sinwar, its mission to the United Nations said.

Hezbollah was also defiant, announcing "the transition to a new and escalating phase in the confrontation with Israel".

U.S. Secretary of State Antony Blinken held separate phone calls on Thursday with leaders in Saudi Arabia and Qatar aimed at ending the conflict in the Middle East, the State Department said.

NO COMFORT, NO COMPROMISE

Families of Israeli hostages said that while the killing of Sinwar was a significant achievement, it would not be complete while hostages are still in Gaza.

Avi Marciano, the father of Noa Marciano, who was killed in captivity by Hamas, told Israeli broadcaster KAN that "the monster, the one who took her from me, who had the blood of all our daughters on his hands, finally met the gates of hell."

"A little justice, but no comfort," he said. "There will be comfort only when Naama, Liri, Agam, Daniela and Karina, our girls' friends, return home."

In Khan Younis in the south of the Gaza Strip, a displaced Palestinian named Thabet Amour told Reuters the Palestinian fight would continue.

"This is resistance that does not disappear when men disappear," he said. "The assassination of Sinwar will not lead to the end of the resistance or to a compromise or surrender and raising the white flag."

The mayor of a major town in south Lebanon was among 16 people killed when an Israeli airstrike destroyed its municipal headquarters in the biggest attack on an official Lebanese state building since the Israeli air campaign began.

Lebanese officials denounced the incident, which also wounded more than 50 people in Nabatieh, a provincial capital, saying it was proof that Israel's campaign against the Hezbollah armed group was now shifting to target the Lebanese state, Reuters reported.

The Israelis "intentionally targeted a meeting of the municipal council to discuss the city's service and relief situation" to aid people displaced by the Israeli campaign, caretaker Prime Minister Najib Mikati said.

Israel launched its ground and air campaign in Lebanon to dismantle Hezbollah after a year during which the Iran-backed militant group fired across the border in support of Palestinian militants Hamas in Gaza.

Fears of a regional conflict have grown after Israel promised to retaliate for an Iranian missile attack on Oct. 1.

The U.S. said on Wednesday it struck five underground weapons storage locations in Houthi-controlled areas of Yemen, the latest in more than a dozen U.S. attacks on Houthi-linked targets this month.

Iran-aligned Houthi fighters in Yemen who say they are acting in solidarity with Palestinians in Israel's year-long war in Gaza have carried out nearly 100 attacks on ships crossing the Red Sea since November.

Israel also launched strikes at Syria's Mediterranean port city of Latakia early on Thursday, Syrian state news agency SANA reported.

Firefighters are working on extinguishing fires that had broken out, SANA added, while Syrian state television reported the country's air defences had confronted Israeli targets over

Latakia.

EVACUATION NOTICE

Israel first issued an evacuation notice for Nabatieh, a city of tens of thousands of people, on Oct. 3. At the time, the city's Mayor Ahmed Kahil told Reuters he would not leave.

Asked about Israeli strike on Nabatieh, State Department spokesperson Matthew Miller declined to comment on the circumstances of specific strikes but said the U.S. understands Hezbollah operates from places including civilian homes and supported limited strikes to target the group.

"Obviously, we'd not want to see entire villages destroyed. We don't want to see civilian homes destroyed," Miller said.

Israel said on Wednesday it struck dozens of Hezbollah targets in the Nabatieh area and its navy also hit dozens of targets in southern Lebanon.

It said it had "dismantled" a tunnel network used by Hezbollah's elite Radwan Forces in the heart of a town near the border with Israel, publishing a video showing multiple explosions rocking a cluster of buildings. Lebanese officials said it was the small town of Mhaibib.

Israeli operations in Lebanon have killed at least 2,350 people over the last year, according to the health ministry, and more than 1.2 million people have been displaced. The death toll does not distinguish between civilians and combatants but includes hundreds of women and children.

Around 50 Israelis, both soldiers and civilians, have been killed in the same period, according to Israel.

PEACEKEEPERS REPORT MORE FIRE

The U.N. mission in Lebanon (UNIFIL) said its peacekeepers observed an Israeli tank firing at their watchtower near southern Lebanon's Kfar Kela on Wednesday morning. Two cameras were destroyed, and the tower was damaged, UNIFIL said.

There was no immediate comment from the Israeli military on the UNIFIL statement.

Israel has previously called on the United Nations to move members of the UNIFIL peacekeeping force in southern Lebanon out of the combat zone for their safety.

UNIFIL says its troops have come under Israeli attack several times, though Israel has disputed accounts of those incidents.

Israeli Defence Minister Yoav Gallant, on a visit to northern Israel near the border, said Israel would not halt its assault on Hezbollah to allow negotiations.

"We will hold negotiations only under fire. I said this on day one, I said it in Gaza and I am saying it here," he said according to a statement from his office.

Pentagon chief Lloyd Austin on Wednesday spoke to Gallant and "reinforced the importance of taking all necessary measures to ensure the safety and security of UNIFIL forces and the Lebanese Armed Forces," according to the Department of Defense.

At least one Israeli strike hit Beirut's southern suburbs early on Wednesday morning, Reuters witnesses said, hours after the U.S. said it opposed the scope of Israeli attacks in Beirut amid a rising death toll and fears of wider regional escalation.

Reuters witnesses heard two blasts and saw plumes of smoke emerging from two separate neighborhoods. It came after Israel issued an evacuation order early on Wednesday which mentioned only one building.

The Israeli military has in recent weeks carried out strikes on Beirut's southern suburbs, a Hezbollah stronghold, without advance warnings, or issued a warning for one area while striking more broadly.

The Israeli military said it conducted a strike on an underground Hezbollah weapons stockpile in the southern Beirut suburb of Dahiyeh.

"Prior to the strike, numerous steps were taken to mitigate the risk of harming civilians, including advancing warnings to the population in the area," the Israeli military said.

Israeli military evacuation orders were also affecting more than a quarter of Lebanon, according to the U.N. refugee agency, two weeks after Israel began incursions into the south of the country that it says are aimed at driving back Hezbollah.

Some Western countries have been pushing for a ceasefire between the two neighbors, as well as in Gaza, though the United States says it continues to support Israel and was sending an anti-missile system and troops.

On Tuesday, State Department spokesperson Matthew Miller said the U.S. had expressed its concerns to Prime Minister Benjamin Netanyahu's administration on the recent strikes.

"When it comes to the scope and nature of the bombing campaign that we saw in Beirut over the past few weeks, it's something that we made clear to the government of Israel we had concerns with and we were opposed to," he told reporters, adopting a harsher tone than Washington has taken so far.

The last time Beirut was hit was on Oct. 10, when two strikes near the city center killed 22 people and brought down entire buildings in a densely populated neighborhood.