Iranian President Ebrahim Raisi was confirmed dead in the helicopter crash in which he was travelling in a mountainous area of northwest Iran.
Rescuers found the burned remains of the aircraft on Monday morning after he had been missing for more than 12 hours.
“President Raisi, the foreign minister and all the passengers in the helicopter were killed in the crash,” confirmed by the senior Iranian official.
Iran’s Mehr news agency reported “all passengers of the helicopter carrying the Iranian president and foreign minister were martyred”.
State TV said it had smashed into a mountain – there has been no official word on the cause but there was thick fog in the area at the time.
“President Raisi’s helicopter was completely burned in the crash unfortunately, all passengers are feared dead,” according to an official.
The search involving civilian and military teams had been hampered by fog and the remote location.
Five days of national mourning have been declared by Supreme Leader Ayatollah Ali Khamenei.
First Vice President Mohammad Mokhber has been put in charge, said Iran’s IRNA news agency, and elections must be held within 50 days
Mr Raisi, 63, who was seen as a frontrunner to succeed Ayatollah Khamenei, was travelling from Azerbaijan where he had inaugurated a dam with the country’s president.
The governor of East Azerbaijan province, officials and bodyguards are also believed to be among the eight people killed.
The helicopter was travelling in a convoy of three aircraft and Iranian media initially described it as a “hard landing”.
Iranian news agency IRNA said he was flying in an American-made Bell 212 helicopter purchased in the early 2000s.
President Raisi was elected in 2021 in a vote that had the lowest turnout in the Islamic republic’s history.
The president was sanctioned by the US over the mass execution of political prisoners at the end of the Iran-Iraq war in 1988.
His time in charge included major protests over Mahsa Amini – the woman who died after she was arrested for allegedly not wearing her hijab properly.
Iran also took the unprecedented decision in April to launch a drone and missile attack on Israel.
Sky’s Middle East correspondent, Alistair Bunkall, says the president was not a universally popular figure and that many inside Iran will celebrate his death.
He says the country’s approach to foreign affairs after his death is likely to be “business as usual”.