Updated 9.50pm with Israeli prime minister's reaction.
Israel said Thursday its forces killed Hamas chief Yahya Sinwar in a Gaza operation, dealing a massive blow to the group it has been fighting since the October 7, 2023 attack.
"The mass murderer Yahya Sinwar, responsible for the massacre and atrocities of October 7, was eliminated... by IDF (Israeli military) soldiers," Foreign Minister Israel Katz said in a statement.
The military later confirmed that "after a year-long pursuit", soldiers "eliminated Yahya Sinwar, the leader of the Hamas terrorist organisation, in an operation in the southern Gaza Strip" on Wednesday.
Hamas has not confirmed his death.
Israel accuses Sinwar of masterminding the October 7 attack, the deadliest in Israeli history, and had been hunting him down since the start of the Gaza war.
He rose through the ranks of the Palestinian militant group to become first its leader in Gaza, then its overall head after the killing in July of political chief Ismail Haniyeh.
Israel's Netanyahu says 'evil suffered heavy blow' with Sinwar's death
Israeli Prime Minister Benjamin Netanyahu said that the killing of Hamas chief Yahya Sinwar in Gaza was a heavy blow to the Palestinian group that could lead to its decline.
In a video statement, Netanyahu said: "The person who committed the most terrible massacre in the history of our nation since the Holocaust, the mass murderer who murdered thousands of Israelis and kidnapped hundreds of our citizens, was eliminated today by our heroic soldiers."
Netanyahu said that "today, evil has suffered a heavy blow, but the task before us is not yet complete."
"The war... is not over yet. And it is difficult, and it exacts heavy prices from us."
But Netanyahu said that Sinwar's killing showed "why we insisted on not ending the war" earlier despite increasing domestic and international pressure.
He mentioned specifically the decision in May "to enter Rafah, the fortified stronghold of Hamas where Sinwar and many of the murderers hid" in southern Gaza, in defiance of global calls against the military operation.
Addressing relatives of hostages still held in Gaza since the Hamas attack, the Israeli leader called Sinwar's death "an important moment in the war."
"We will continue with all our strength until the return home of all your loved ones."
Netanyahu also directed a message to Palestinians in war-battered Gaza, saying "Sinwar ruined your life."
"He was killed when he fled in panic from our soldiers," Netanyahu said.
"His elimination is an important landmark in the decline of the evil rule of Hamas."
According to Netanyahu, "Hamas will no longer rule Gaza. This is the beginning of the day after Hamas, and this is an opportunity for you, the residents of Gaza, to finally break free from its tyranny."
The prime minister also called on militants to free hostages if they want to live.
"Whoever lays down his weapon and returns our hostages -- we will allow him to go on living," he said.
Israel's announcement on Sinwar comes weeks after it assassinated Hezbollah chief Hassan Nasrallah in a massive strike in Lebanon, where the Israeli military has been at war since late September.
A slew of other Iran-backed militant commanders have also been killed in recent months.
Israel said earlier this year that it had killed Mohammed Deif, Hamas's military chief, though the Palestinian group has not confirmed it.
Deif stood accused of planning, with Sinwar, the October 7 attack.
With Hamas massively weakened more than a year into the Gaza war, Sinwar's death could deal a seismic blow to the organisation.
Before the Israeli foreign minister confirmed Sinwar's death, the military said in a brief statement that during "operations in the Gaza Strip, three terrorists were eliminated", with the Hamas leader possibly one of them.
An Israeli security official told AFP that the military was conducting a DNA test on a militant's body to confirm whether it was Sinwar's.
In a post on X, Israel's Defence Minister Yoav Gallant said the country would "reach every terrorist and eliminate them".
US President Joe Biden was briefed aboard Air Force One while heading to Germany and was being kept informed of developments, a US official said Thursday.
- War on many fronts -
Israel has been at war with Hamas since the October 7 attack, which resulted in the deaths of 1,206 people, mostly civilians, according to an AFP tally of official Israeli figures.
Israel's retaliatory campaign in Gaza has killed 42,438 people, the majority civilians, according to data from the health ministry in the Hamas-run territory, which the UN considers reliable.
Following the attack, Prime Minister Benjamin Netanyahu vowed to crush Hamas and bring home all 251 hostages seized by militants in their cross-border onslaught. Ninety-seven remain in Gaza, including 34 Israeli officials say are dead.
Israel has since expanded the scope of its operations to Lebanon, where Hamas ally Hezbollah opened a front against Israel by launching low-intensity cross-border strikes that forced tens of thousands of Israelis to flee their homes.
Israel on Thursday launched strikes on the south Lebanese city of Tyre, where the militant group and its allies hold sway.
Israel also issued evacuation warnings for civilians in parts of Lebanon's eastern Bekaa Valley, a Hezbollah stronghold.
It had earlier struck a Hezbollah target in Syria, according to a war monitor, while Israel's main ally the United States used heavy bombers to hit rebel targets in Yemen.
Syria, the Huthi rebels in Yemen, Hezbollah in Lebanon and Hamas in Gaza all belong to the "axis of resistance" of groups aligned with Iran.
Tehran on October 1 conducted a missile strike on Israel, over which Israel has vowed to retaliate, sparking concern around the world that what is already a war on multiple fronts could morph into an all-out regional conflict.
- Iran warning -
Iran's Revolutionary Guards chief Hossein Salami on Thursday warned Tehran would hit Israel "painfully" if it attacks Iranian targets.
The Syrian Observatory for Human Rights, a Britain-based monitor, said the Israeli raid on the Syrian city of Latakia targeted a "weapons depot belonging to Hezbollah".
The Israeli military did not comment on the strike when contacted by AFP.
In Huthi-controlled areas of Yemen, the United States conducted multiple B-2 bomber strikes on weapons storage facilities, according to the US military and defence department.
The Huthis' political bureau said "the American aggression will not pass without a response", and vowed to continue the group's "support and assistance to Gaza and Lebanon".
The war in Lebanon since last month has left at least 1,373 people dead, according to an AFP tally of Lebanese health ministry figures, though the real toll is likely higher.
Israeli troops and Hezbollah fighters have been clashing near Lebanon's southern border, where Hezbollah on Thursday said it hit four Israeli tanks with guided missiles.
Rescue workers affiliated with the Amal party, a Hezbollah ally, in the southern city of Qana were digging through the rubble of several buildings destroyed in strikes this week.
"More than 15 buildings have been completely destroyed, total destruction in a neighbourhood in Qana," said Mohammed Nasrallah Ibrahim, one of the rescuers.
Israel has faced criticism over its strikes in Lebanon, including from its tops arms supplier the US.
- Hunger in Gaza -
In northern Gaza's Jabalia, two hospitals said Israeli air strikes on a school sheltering displaced people killed at least 14 people.
The military reported that it had hit militants.
Some 345,000 Gazans face "catastrophic" levels of hunger this winter after aid deliveries fell, a UN-backed assessment said Thursday, warning of the persistent risk of famine.
Nearly 100 percent of Gaza's population now lives in poverty, with a "staggering" unemployment rate of nearly 80 percent, the UN's International Labour Organization said on Thursday.
The impact of the war on Gaza "will be felt for generations to come," said the ILO's Ruba Jaradat.