Iranian President Ebrahim Raisi has died after the helicopter he was travelling on crashed in a mountainous area in the northwest of Iran.

Rescue teams located the crash site on Monday morning, at which point the president and his foreign minister 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,” a senior Iranian official told Reuters.

Iran’s Mehr news agency reported that “all passengers of the helicopter carrying the Iranian president and foreign minister were martyred”.

State TV reported that images from the crash showed the aircraft smashed into a mountain peak, although there was no official word on the cause of the crash.

“President Raisi’s helicopter was completely burned in the crash … unfortunately, all passengers are feared dead,” an official told Reuters.

State news agency IRNA said the president was flying in an American-made Bell 212 helicopter.

Raisi was seen as a frontrunner to succeed Ayatollah Ali Khamenei as Iran’s Supreme Leader, was travelling after a visit to the border with Azerbaijan when the helicopter crashed.

Iran’s foreign minister, Hossein Amirabdollahian, the governor of East Azerbaijan province and other officials were also said to have been aboard the chopper when the crash, initially described as a “hard landing”, happened amid fog on Sunday.

The chief of staff of Iran’s army had ordered all the resources of the military and the elite Revolutionary Guard to be put to use in search and rescue operations, which had been hampered by the bad weather.