Hamas leader Ismail Haniyeh was killed in Iran on Wednesday, the Palestinian group Hamas and Iran's elite Revolutionary Guards said in separate statements.
The Islamist faction mourned the death of Haniyeh, who it said was killed in "a treacherous Zionist raid on his residence in Tehran".
Hanieh attended Iran's new president's swearing-in ceremony on Tuesday.
"Early this morning, the residence of Ismail Haniyeh in Tehran was struck, resulting in his and one of his bodyguards' martyrdom. The cause is under investigation and will be announced soon," the Revolutionary Guards said.
