Prime Minister Benjamin Netanyahu's promises to press on with Israel's wars in Gaza and Lebanon dashed hopes on Friday that the killing of Hamas leader Yahya Sinwar might help end more than a year of escalating conflict in the Middle East.

Lebanese militant group Hezbollah meanwhile vowed to escalate fighting against Israel and its backer Iran said "the spirit of resistance" would be strengthened by the death of its Palestinian ally Sinwar in Gaza.

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.

Netanyahu called Sinwar's killing a milestone late on Thursday but vowed to keep up the war, which in recent weeks expanded from fighting against Palestinian group Hamas in Gaza into an invasion of southern Lebanon and the bombardment of large swathes of the country.

"The war, my dear ones, is not yet over," Netanyahu told Israelis, saying fighting would continue until hostages held by Hamas are released.

"We have before us a great opportunity to stop the axis of evil and create a different future," he added, referring to Iran and its militant allies across the region in Gaza, Lebanon, Syria, Iraq and Yemen.

Netanyahu's comments contrasted with Western leaders, including U.S. President Joe Biden, who said Sinwar's death offered a chance for the conflict to end.

The U.S. wants to kick-start ceasefire talks and secure the release of hostages, U.S. State Department spokesperson Matthew Miller said, adding that Sinwar had been refusing to negotiate.

"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.

One senior diplomat working in Lebanon told Reuters that hopes Sinwar's death would end the war appeared misplaced.

"We had hoped, really throughout this, that getting rid of Sinwar would be the turning point where the wars would end ... where everyone would be ready to put their weapons down. It appears we were once again mistaken," the diplomat said.

Months of efforts by Israel's chief backer the United States to broker ceasefires with Hamas and Hezbollah have failed as Israel has pressed on with its wars, and its arch foe Iran has looked largely powerless to match Israel's military might, including U.S. weapons.

The conflict has caused the first direct Iranian-Israeli confrontations, including missile attacks on Israel in April and Oct. 1. Netanyahu has vowed to respond to the October attack, which caused little damage. Washington has pressed Israel to limit targets and not strike Iranian energy facilities or nuclear sites.

Tracked and killed

Sinwar, 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 on Wednesday by Israeli troops initially unaware they had caught their 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. He was tracked by the drone as he lay dying, the video showed. As the drone hovered nearby, the video showed him throwing a stick at it, in an apparent act of desperation.

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

He masterminded the Oct. 7, 2023 attacks in southern Israel that killed some 1,200 people, according to Israeli authorities. Israel responded by invading Gaza, so far killing more than 42,000 people, according to Palestinian officials.

Hezbollah, which began firing rockets at Israel in support of its Hamas ally on Oct. 8, is the target of Israel's intensifying assault on Lebanon, which has killed more than 2,000 people and displaced 1.2 million.

Israel has now killed several of Hamas' top leaders and in a matter of weeks decapitated the Hezbollah leadership , mainly through air strikes.

The killings have dealt a blow to what anti-Israeli forces call the Axis of Resistance: a group of proxy militant groups that Iran has spent decades supporting across the region.

Iran showed no sign Sinwar's killing would shift its support. "The spirit of resistance will be strengthened," 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".

The Israeli military said on Friday it had also killed Muhammad Hassin Ramal, Hezbollah’s commander of the Tayibe area in southern Lebanon.

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

Avi Marciano, 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."