Ismail Haniyeh, political bureau chief of the Palestinian resistance group Hamas, has been killed in Iran, according to a statement from Hamas and Iranian officials.

Hamas said its leader was killed early on Wednesday following an Israeli raid targeting his residence in Tehran.

In a statement, the group mourned the death of Haniyeh, 62, who it said was killed in "a treacherous Zionist raid on his residence in Tehran after participating in the inauguration ceremony of the new Iranian president."

Haniyeh, a prominent figure in the Palestinian political and resistance group, has been a key figure before and during Israel's genocidal war on besieged Gaza.

Iran's Nournews says Haniyeh's residence was hit by an "airborne projectile", implying some kind of missile.

"Further investigations are underway to determine the details of this terrorist operation," it added.

The Iranian government announced an investigation into the killing, with results expected to be released soon.

"The residence of Ismail Haniyeh, head of the political office of Hamas Islamic Resistance, was hit in Tehran, and as a result of this incident, him and one of his bodyguards were martyred," said a statement by the Iran's Revolutionary Guard's Sepah news website. Haniyeh was in Tehran to attend Iranian President Masoud Pezeshkian’s swearing-in ceremony on Tuesday.

A top Hamas official described the assassination of the Hamas chief as a "cowardly act that will not go unpunished," according to Hamas-run Al-Aqsa TV.

No one immediately claimed responsibility for the assassination but suspicion immediately fell on Israel, which has vowed to kill Haniyeh and other leaders of Hamas. Israel has killed many close and extended family members of Haniyeh in its ongoing carnage in Gaza.

Analysts on Iranian state television immediately began blaming Israel for the attack.

Israel itself did not immediately comment but it often doesn't when it comes to assassination carried out by its notorious Mossad intelligence agency.

Israel is suspected of running a years-long assassination campaign targeting Iranian nuclear scientists and others associated with its atomic programme.

Senior Palestinian official Hussein al Sheikh in the occupied West Bank condemned Haniyeh’s assassination as a “cowardly act.”

“We strongly denounce and condemn the assassination of the head of the Political Bureau, the national leader, Ismail Haniyeh,” the Palestinian Authority’s civil affairs chief wrote on X.

“We consider it a cowardly act, this pushes us to remain more steadfast in the face of the occupation, and the necessity of achieving the unity of the Palestinian forces and factions.”