Search and rescue teams were scouring a fog-shrouded mountain area of northwest Iran Monday after President Ebrahim Raisi's helicopter went missing in what state media described as an accident.

Fears grew for the 63-year-old ultraconservative after contact was lost with the aircraft carrying him as well as Foreign Minister Hossein Amir-Abdollahian and others in East Azerbaijan province on Sunday, reports said.

After hours of searching, state TV reported early Monday that a Turkish drone appeared to have detected "the coordinates of the accident" and informed Iranian rescue teams.

"Rescue teams have been dispatched to the site," it added.

State television first reported Sunday afternoon that "an accident happened to the helicopter carrying the president" in the Jolfa region of East Azerbaijan province.

"The harsh weather conditions and heavy fog have made it difficult for the rescue teams to reach the accident site," said one broadcaster, as the massive search effort later continued through the night.

Interior Minister Ahmad Vahidi said the helicopter "made a hard landing" in bad weather and that it was "difficult to establish communication" with the aircraft.

He urged people to get their information "only from state television", and not listen to foreign media channels Iran deems hostile to the Islamic republic.

Raisi's convoy had included three helicopters, and the other two had "reached their destination safely", said the Tasnim news agency.

Supreme leader Ayatollah Ali Khamenei urged Iranians to "not worry" about the leadership of the Islamic republic, saying "there will be no disruption in the country's work".

"We hope that Almighty God will bring our dear president and his companions back in full health into the arms of the nation," he said in a nationally televised address as Muslim faithful prayed for Raisi's safe return.

Expressions of concern and offers to help came from abroad, including Iraq, Kuwait, Qatar, Saudi Arabia, Syria, Russia and Turkey, as well as from the European Union which activated its rapid response mapping service to aid in the search effort.

Iran's foreign ministry spokesman Nasser Kanani expressed gratitude for "governments and international organisations for their sympathy and offer of help in the search and rescue operations."

- Massive search effort -

Iran's cabinet held an emergency meeting led by Vice President Mohammad Mokhber after the incident, the IRNA news agency reported.

More than 60 rescue teams using search dogs and drones were sent to the mountainous protected forest area of Dizmar near the town of Varzaghan, IRNA said.

Army, Revolutionary Guard and police officers joined the search, authorities said, as TV stations showed pictures of Red Crescent teams walking up a hill in the mist, and rows of waiting emergency response vehicles.

Raisi had visited the northwestern province to inaugurate a dam project together with Azerbaijan's President Ilham Aliyev, on their common border.

Aliyev said in a post on X that "we were profoundly troubled by the news of a helicopter carrying the top delegation crash-landing in Iran".

"Our prayers to Allah Almighty are with President Ebrahim Raisi and the accompanying delegation," he said, also offering "any assistance needed".

Foreign countries were closely following the search at a time of high regional tensions over the Gaza war between Israel and Hamas since October 7 that has drawn in other armed groups in the Middle East.

A US State Department spokesman said: "We are closely following reports of a possible hard landing of a helicopter in Iran carrying the Iranian president and foreign minister", adding that "we have no further comment at this time".

US President Joe Biden has been briefed on the crash, an American official said on condition of anonymity.

- 'Servant of the people' -

Raisi has been president since 2021 when he succeeded the moderate Hassan Rouhani, at a time when the economy was battered by US sanctions over Iran's contested nuclear programme.

Iran saw a wave of protests triggered by the death in custody of Iranian-Kurdish woman Mahsa Amini in September 2022 after her arrest for allegedly flouting dress rules for women.

In March 2023, regional rivals Iran and Saudi Arabia signed a surprise deal that restored diplomatic relations.

The Gaza war sent regional tensions soaring again and a series of tit-for-tat escalations led to Tehran launching hundreds of missiles and rockets directly at Israel in April this year.

In a speech following Sunday's dam inauguration, Raisi emphasised Iran's support for Palestinians, a centrepiece of its foreign policy since the 1979 Islamic revolution.

"We believe that Palestine is the first issue of the Muslim world, and we are convinced that the people of Iran and Azerbaijan always support the people of Palestine and Gaza and hate the Zionist regime," said Raisi.

Hamas, which the United States and European Union consider a terrorist group, said that "in this painful incident, we express our full solidarity with the Islamic Republic of Iran, its leadership, government and people". 

© Agence France-Presse