Hamas leader Yahya Sinwar, mastermind of the Oct. 7, 2023, attack that triggered the Gaza war, was killed on Thursday, Israeli Foreign Minister Israel Katz said.

His killing by Israeli forces operating in Gaza marks a huge success for Israel and a pivotal event in the year-long war - although there are a number of possible scenarios.

"Mass murderer Yahya Sinwar, who was responsible for the massacre and atrocities of October 7, was killed today by IDF soldiers," Katz said in a statement.

"This is a great military and moral achievement for Israel and a victory for the entire free world against the axis of evil of radical Islam led by Iran," Katz said.

"Sinwar's assassination creates the opportunity for the immediate release of the hostages and to bring about a change that will lead to a new reality in Gaza - without Hamas and without Iranian control."

Earlier, the Israeli army and police carried out DNA checks on the corpse of the man believed to be that of their arch foe.

There was no immediate comment from Hamas.

In Israel, families of hostages held by Hamas in Gaza said they hoped that a ceasefire could now be reached that would bring home the captives. In Gaza, residents said they believed the war would go on.

The demise of Sinwar is a major boost to the Israeli military and Prime Minister Benjamin Netanyahu as the devastating war in the Palestinian enclave grinds on into a second year.

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.

His death could dial up hostilities in the Middle East where the prospect of an even wider conflict has grown.

But the end of the man who planned the attack last year in which fighters killed 1,200 people in Israel and captured more than 250 hostages could also help push forward stalled efforts to end the war that attack triggered. During the year-long conflict Israel has killed more than 42,000 Palestinians.

Israel's Army Radio said the incident had occurred during a ground operation in the city of Rafah in the southern Gaza Strip during which Israeli troops killed three militants and took their bodies.

A ruthless enforcer once tasked with punishing Palestinians suspected of informing for Israel, Sinwar made his name as a prison leader.

He emerged as a street hero from a 22-year Israeli sentence for masterminding the abduction and murder of two Israeli soldiers and four Palestinians. He then quickly rose to the top of the Hamas ranks. He was dedicated to eradicating Israel.

Israel has carried out relentless airstrikes and ground operations to try and reach Netanyahu's goal of destroying Hamas.

In northern Gaza on Thursday, Israeli strikes killed 19 Palestinians including children at a school in the Jabalia camp that is sheltering displaced people, a Gaza health ministry official told Reuters.