A helicopter carrying Iranian president Ebrahim Raisi and his foreign minister crashed on Sunday as it was crossing mountain terrain in heavy fog on the way back from a visit to the border with Azerbaijan, an Iranian official told Reuters.
The official said the lives of Raisi and Foreign Minister Hossein Amirabdollahian were "at risk following the helicopter crash."
"We are still hopeful but information coming from the crash site is very concerning," said the official, speaking on condition of anonymity.
The bad weather was complicating rescue efforts, the state news agency IRNA reported.
State TV stopped all its regular programming to show prayers being held for Raisi across the country and, in a corner of the screen, live coverage of rescue teams searching the mountainous area on foot in heavy fog.
The 63-year-old was elected president at the second attempt in 2021, and since taking office has ordered a tightening of morality laws, overseen a bloody crackdown on anti-government protests, and pushed hard in nuclear talks with world powers.
In Iran's dual political system, split between the clerical establishment and the government, it is the supreme leader rather than the president who has the final say on all major policies.
But many see Raisi as a strong contender to succeed his 85-year-old mentor, Supreme Leader Ayatollah Ali Khamenei, who has strongly endorsed Raisi's main policies.
Interior Minister Ahmed Vahidi told state TV only that one of the helicopters in a group of three had come down hard, and that authorities were awaiting further details.
Raisi had been at the Azerbaijani border to inaugurate the Qiz-Qalaisi Dam, a joint project.