A helicopter carrying Iran’s hard-line president and foreign minister has crashed in a remote and mountainous region near the country’s border with Azerbaijan, with the fate of the two leaders unknown.

Rescuers were despatched on Monday morning (AEST) but have been unable to pinpoint the crash site, as rugged terrain and fog hamper the operation.

Iran state media has described the accident as a “hard landing”.

Later, CNN reported a signal had been received from the helicopter and the mobile phone of one of the crew. Military forces were heading to the crash site and hoped to have some “good news”.

President Ebrahim Raisi was travelling with Iran’s Foreign Minister Hossein Amirabdollahian, the governor of Iran’s East Azerbaijan province and other officials, the state-run IRNA news agency reported.

State TV said the incident happened near Jolfa, a city on the border with Azerbaijan, some 600 kilometres north-west of the Iranian capital, Tehran.

One local government official used the word “crash” to describe the incident.But he acknowledged to an Iranian newspaper that he had yet to reach the site.

Neither IRNA nor state TV offered any information on Raisi’s condition.

“The esteemed president and company were on their way back aboard some helicopters and one of the helicopters was forced to make a hard landing due to the bad weather and fog,” Interior Minister Ahmad Vahidi said in comments aired on state TV.

“Various rescue teams are on their way to the region but because of the poor weather and fogginess it might take time for them to reach the helicopter.”

He added: “The region is a bit [rugged] and it’s difficult to make contact. We are waiting for rescue teams to reach the landing site and give us more information.”

Rescuers were attempting to reach the site, state TV said, but had been hampered by bad weather.

Heavy rain and fog were reported, with some wind. IRNA called the area a “forest”, and the region is also known to be mountainous.

A rescue team searches in foggy and frigid conditions. Photo: Mehr News Agency

Raisi was in Azerbaijan early on Sunday to inaugurate a dam with Azerbaijan’s President Ilham Aliyev. The dam is the third built on the Aras River by the two nations.

The visit came despite chilly relations between the nations, including over a gun attack on Azerbaijan’s Embassy in Tehran in 2023, and Azerbaijan’s diplomatic relations with Israel, which Iran’s Shiite theocracy views as its main enemy in the region.

Iran flies a variety of helicopters in the country, but international sanctions make it difficult to obtain parts for them. Its military air fleet also largely dates back to before the 1979 Islamic Revolution.

Raisi, 63, is a hard-liner who formerly led the country’s judiciary. He is viewed as a protégé of Iran’s Supreme Leader Ayatollah Ali Khamenei and some analysts have suggested he could replace the 85-year-old leader after his death or resignation from the role.

Raisi won Iran’s 2021 presidential election, a vote that had the lowest turnout in the Islamic Republic’s history.

Iran’s President Ebrahim Raisi at the site of a road and rail bridge project ahead of Sunday’s crash. Photo: Office of the President of the Islamic Republic of Iran (via Getty)

Raisi is sanctioned by the US in part over his involvement in the mass execution of thousands of political prisoners in 1988 at the end of the bloody Iran-Iraq war.

Under Raisi, Iran enriches uranium at nearly weapons-grade levels and hampers international inspections.

Iran has armed Russia in its war on Ukraine, as well as launched a massive drone-and-missile attack on Israel amid its war against Hamas in the Gaza Strip. It also has continued arming proxy groups in the Middle East, including Yemen’s Houthi rebels and Lebanon’s Hezbollah.

-with AAP