Raisi and the foreign minister are missing after their aircraft came down in mountain terrain near border with Azerbaijan in heavy fog

• Iran president helicopter crash: rescuers search for Ebrahim Raisi – live updates

A rescue operation is under way in the mountains close to the Iranian-Azerbaijani border after one of the helicopters in a convoy carrying Iran’s president, Ebrahim Raisi, was involved in a “hard landing” on Sunday, according to Iranian state media. This is what we know so far.

The incident, which involved one helicopter in a convoy of three, was described by Iranian state television as an accident.

An unnamed Iranian official told Reuters that the lives of the president and his foreign minister, Hossein Amir-Abdollahian, were “at risk” after a “crash” as it was crossing mountain terrain in heavy fog.

Three rescue workers searching for the crashed helicopter were reported missing by the Red Crescent but were later accounted for. A spokesperson said the search and rescue operation will slow down as the weather is expected to get “severely cold” soon with more rain forecast.

Raisi was travelling in Iran’s East Azerbaijan province. State TV described the area of the helicopter incident as being near Jolfa, a city on the border with Azerbaijan.

The president had been in Azerbaijan earlier on Sunday to inaugurate a dam with the country’s president Ilham Aliyev. The dam is the third one that the two nations have built on the Aras River.

Iran’s army chief of staff said all army resources will be used for the search and rescue operations, state TV reported. Maj Gen Mohammad Bagheri has also ordered guards to take part in the search efforts, it said.

Iraq has instructed its interior ministry, the Red Crescent and other relevant bodies to offer help to neighbouring Iran and assist in the search.