Hamas has claimed Haniyeh was killed in a "Zionist raid". Israel is yet to respond to the allegation but in the wake of the 7 October attacks - which killed 1,200 people and saw hundreds taken hostage - Israeli leaders vowed to "crush and destroy Hamas".

Several senior Hamas figures are believed to have been killed by Israel since - including deputy political leader Saleh al-Arouri and Marwan Issa, the deputy commander of Hamas's military wing.

Ismail Haniyeh's three sons and four of his grandchildren were also killed in an Israeli air strike in Gaza in April.

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Ismail Haniyeh had last been seen publicly at the inauguration of Iranian President Masoud Pezeshkian on Tuesday. He met the new president as well as Iran's supreme leader, Ayatollah Ali Khamenei.

Reports say that during the meeting, the president told the Hamas leader that Iran would "stand by the Palestinian people", with Haniyeh thanking Iran for its "honourable position".

The visit to Iran for the inauguration was Haniyeh's final public appearance.

The Washington Institute for Near East Policy wrote in the weeks after the 7 October Hamas attacks, external that "Hamas would not have been able to plan and conduct such an operation without years of Iranian training".

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Although Ismail Haniyeh was considered to be Hamas’s top leader – due to his role leading the Palestinian group’s political operations while living in exile in Qatar and Turkey - there are other high-ranking Hamas figures.

Yahya Sinwar – who Israel holds partly responsible for overseeing the 7 October raid which killed about 1,200 people and led to the kidnappings of more than 200 – has all but disappeared from the Gaza Strip, with Israel still working to discover his whereabouts.

Sinwar is the founder of the Hamas security service known as Majd, which manages internal security matters, investigates suspected Israeli agents and tracks down Israeli intelligence and security services officers.

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Mohammed Deif, the elusive leader of Hamas's military wing – which is known as the Izzedine al-Qassam Brigades – is another senior leader who remains on Israel's most wanted list.

Israel imprisoned him in 2000, but he escaped at the beginning of the second Palestinian uprising, or intifada in the early 2000s. Since then, he has left behind almost no trace. The last time Israeli security forces tried and failed to assassinate Deif was in 2014, during an assault on the Gaza Strip.

Read more about the militant group’s leadership rung here.

Iran's Islamic Revolutionary Guard Corps (IRGC) has offered its condolences following the death of Ismail Haniyeh in Tehran.

A statement shared by its media arm Sepah news said the group was investigating "the cause and dimensions of the incident" and will announce the outcome later.

It added that Haniyeh and one of his bodyguards were "martyred".

The IRGC is a major military, political and economic force in Iran, with close ties to the supreme leader, Ayatollah Ali Khamenei.

Hamas said in a statement that its leader Ismail Haniyeh was killed at his residence in Tehran in a raid by Israel.

The Palestinian group controlling Gaza said that Haniyeh was "killed in a treacherous Zionist raid".

Israel is yet to respond or issue a statement.

The group said he had participated in the inauguration ceremony of the new Iranian president Masoud Pezeshkian on Tuesday.

"The Islamic Resistance Movement Hamas mourns to our great Palestinian people, to the Arab and Islamic nation, and to all the free people of the world," it added.

Most Hamas leaders keep a low public profile, while others have spent much of their lives evading assassination attempts by Israel.

Image source, Reuters

Ismail Haniyeh is widely considered Hamas's overall leader and has been a prominent member of the movement since 1980.

He briefly served as Palestinian prime minister - appointed in 2006, but was dismissed a year later after Hamas ousted the rival Fatah Party from the Gaza Strip in a week of deadly violence.

He was elected head of Hamas's political bureau in 2017 and the US Department of State designated him a terrorist in 2018.

He has lived in Qatar for the past several years.

Hamas has said its leader Ismail Haniyeh has been killed in Tehran in an Israeli raid.

In a statement released on Wednesday morning, Hamas said Haniyeh was killed at his residence in Tehran while on a visit to attend the inauguration of President Masoud Pezeshkian.

Stay with us as we bring you the latest updates in this developing story.