Israeli Foreign Minister Israel Katz said on Thursday that Hamas leader Yahya Sinwar has been killed.

“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.

Moreover, members of Israel’s security cabinet have been told that Hamas leader Yahya Sinwar, a mastermind of the Oct 7, 2023 attack that triggered the Gaza war, is very likely dead, two officials with knowledge of the matter said on Thursday.

The Israeli military said it was checking the possibility that Sinwar, Israel’s most wanted enemy, was among three militants killed during an operation in the Gaza Strip.

There was no immediate comment from the Palestinian militant group Hamas.

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

If confirmed, the death of Sinwar would represent 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.

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.

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

If his death is confirmed it 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 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 could also help push forward stalled efforts to end the war that attack triggered, during which 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.

It said visual evidence suggested it was likely that one of the men was Sinwar and DNA tests were being conducted. Israel has samples of Sinwar’s DNA from time he spent in an Israeli jail.

“At this stage, the identity of the terrorists cannot be confirmed,” it said in a statement.

Israeli police said in a statement: “Dental images have been submitted to the police forensics lab, and DNA testing is currently in progress.” a police statement said.