Iranian state television said on Sunday that Supreme Leader Ali Khamenei was killed following U.S.-Israeli bombardment.
The broadcaster did not provide details about the circumstances of his death.
State media also reported that 40 days of public mourning were declared in Iran.
The Supreme National Security Council said Khamenei was killed at his office early on Saturday, and that his death would mark the beginning of a “great uprising against the tyrants of the world”.
Iran’s Revolutionary Guard Corps (IRGC) said it would “decisively avenge” Khamenei’s killing, stressing that “the hand of revenge of the Iranian people will not let go of the killers of the Imam.”
The IRGC said martyrdom in the path of Islam and “Greater Iran” represents victory and proximity to the ultimate goal.
It added that Khamenei’s path “will not stop after his martyrdom, but will continue with strength and grandeur.”
The statement urged all segments of society to take part in national defence gatherings to demonstrate unity and cohesion before “the enemies of the nation and terrorists.”
It added that the killing would make the nation more determined to continue what it described as Khamenei’s illuminating path.
U.S. President Donald Trump earlier on Saturday night wrote in a post on his social media platform Truth Social that Khamenei was “dead.”
“Khamenei, one of the most evil people in History, is dead,” Trump wrote.
