The Israeli military says it is "checking the possibility" it has killed Hamas leader Yahya Sinwar.
Sinwar has led Hamas within Gaza since 2017, having joined its ranks in the early 1980s.
The 62-year-old is believed to be the mastermind of the 7 October 2023 attacks.
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A senior Israeli official has told Sky News it is "probable" Sinwar has been killed.
If his death is confirmed, it will mean Israel has eliminated its main target since it began strikes and ground invasions in Gaza in response to the Hamas incursion last year.
"During IDF operations in Gaza, three terrorists were eliminated," the Israeli military said in a statement today.
"The IDF and ISA are checking the possibility that one of the terrorists was Yahya Sinwar. At this stage, the identity of the terrorists cannot be confirmed.
"In the building where the terrorists were eliminated, there were no signs of hostages in the area.
"The forces that are operating in the area are continuing to operate with required caution."
Hamas has not yet commented on the reports its leader may have been killed.
Read more:
Who is Yahya Sinwar?
Photographs circulating on social media claimed to show Sinwar's dead body in the hours before the Israeli military released its statement.
The images have not been independently verified.
Israel is waiting for DNA test results to come back before it can confirm if the body is Sinwar, a senior official in the country has said.
They added that it may take a couple of hours for the results to come through.
Sinwar took over full leadership of Hamas after the killing of Ismail Haniyeh, who was the political leader of the group, in Iran in July.
He is believed to have been hiding in the network of tunnels beneath Gaza since the militant group's attack on Israel last year.
US President Joe Biden has been briefed on Israel's investigation into whether it has killed the Hamas leader, and US officials have been in close contact with Israeli officials throughout Thursday morning, according to a senior administration official.
It comes as Israeli forces continued a more than week-old major air and ground assault in the Jabaliya refugee camp in northern Gaza.
An Israeli strike hit a school sheltering displaced Palestinians today, killing at least 15 people, including five children, according to Gaza's Health Ministry.
The war in Gaza is now more than a year old - with Israel having killed more than 42,000 Palestinians in response to Hamas' incursion on 7 October last year, according to the Gaza health ministry.
Hamas killed some 1,200 people and captured around 250 hostages when its militants entered Israel,
(c) Sky News 2024: Israeli military says it is 'checking possibility' it has killed Hamas leader Yahya Sinwar
Who is Hamas leader Yahya Sinwar?
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