Top Hamas leader Ismail Haniyeh has been killed in Iran, the group has said.

In a statement released on Wednesday, Hamas said Haniyeh was killed in an Israeli raid on his residence in Tehran.

A number of other senior Hamas figures, including Palestinian President Mahmoud Abbas, have described Haniyeh's death as an "assassination" and vowed to retaliate.

The Iranian Revolutionary Guard Corps said the cause of the "incident" was not immediately clear but was "being investigated", AFP news agency reported.

According to the group, Haniyeh died after participating in the inauguration ceremony of the new Iranian President Masoud Pezeshkian who was sworn in on Tuesday.

Hamas, the Palestinian group controlling Gaza, said Haniyeh was "killed in a treacherous Zionist raid".

The group's political bureau member Musa Abu Marzuk said it was a "cowardly act" and one which "will not go unanswered"; while another senior Hamas official, Sami Abu Zuhri, said the group will "continue on its path".

"This assassination by the Israeli occupation of Brother Haniyeh is a grave escalation that aims to break the will of Hamas and the will of our people and achieve fake goals," Sami Abu Zuhri told Reuters news agency.

Israel is yet to respond or issue a statement.

EPA Ismail Haniyeh was surrounded by Iranian lawmakers at the Iranian parliament in Tehran on 30 July.

Ismail Haniyeh, surrounded by Iranian lawmakers at the Iranian parliament in Tehran on Tuesday.

Haniyeh, 62, was widely considered Hamas's overall leader.

He was a prominent member of the group's movement in the late 1980s and was imprisoned by Israel for three years in 1989 as it cracked down on the first Palestinian uprising.

He was then exiled in 1992 to a no-man's-land between Israel and Lebanon, along with a number of Hamas leaders.

Haniyeh was appointed Palestinian prime minister in 2006 by President Mahmoud Abbas after Hamas won the most seats in national elections, but he was dismissed a year later after the group ousted Mr Abbas' Fatah party from the Gaza Strip in a week of deadly violence.

Haniyeh rejected his sacking as "unconstitutional", stressing that his government "would not abandon its national responsibilities towards the Palestinian people", and continued to rule in Gaza.

He was elected head of Hamas's political bureau in 2017.

In 2018, the US Department of State designated Haniyeh a terrorist. He had lived in Qatar for the past several years.