Hamas chief Ismail Haniyeh and one of his bodyguards were killed after their residence was targeted in Iran, the Palestinian group said in a statement today.
Hamas said Ismail Haniyeh was killed in "a treacherous Zionist raid on his residence in Tehran" Tuesday morning. The group said an investigation is on to find out more details about the attack.
Haniyeh was in the Iranian capital to attend the swearing-in of Iran's president Masoud Pezeshkian.
"Brother, leader, mujahid Ismail Haniyeh, the head of the movement, died in a Zionist strike on his headquarters in Tehran after he participated in the inauguration of the new (Iranian) president," the statement read.
A senior Hamas official said Ismail Haniyeh's killing "will not go unanswered". "The assassination of leader Ismail Haniyeh is a cowardly act and will not go unanswered," Hamas policial bureau member Musa Abu Marzuk said.
Iran's Revolutionary Guards also confirmed his death, saying Haniyeh's residence in Tehran was "hit" and he was killed along with a bodyguard.
The Israeli army did not immediately respond to Haniyeh's killing.
Israel had vowed to kill Ismail Haniyeh and destroy the Hamas group after October 7 attack that resulted in the deaths of 1,195 people, mostly civilians.
Israel's retaliatory military campaign in Gaza has killed at least 39,400 people, according to the health ministry in the Hamas-run territory.
Haniyeh was elected head of the Hamas political bureau in 2017 to succeed Khaled Meshaal. Considered a pragmatist, Haniyeh lived in exile and split his time between Turkey and Qatar.
He had travelled on diplomatic missions to Iran and Turkey during the war, meeting both the Turkish and Iranian presidents.
Haniyeh was said to maintain good relations with the heads of the various Palestinian factions, including rivals to Hamas.
He joined Hamas in 1987 when the militant group was founded amid the outbreak of the first Palestinian intifada, or uprising, against Israeli occupation, which lasted until 1993.
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