Iranian President Ebrahim Raisi, a hardliner and potential successor to Supreme Leader Ayatollah Ali Khamenei, was killed in a helicopter crash in mountainous terrain near the Azerbaijan border, officials and state media said on Monday.

The charred wreckage of the helicopter which crashed on Sunday carrying Raisi, Foreign Minister Hossein Amirabdollahian and six other passengers and crew was found early on Monday after an overnight search in blizzard conditions.

"President Raisi, the foreign minister and all the passengers in the helicopter were killed in the crash," a senior Iranian official told Reuters, asking not to be named because of the sensitivity of the matter.

Raisi's death was later confirmed in a statement on social media by Vice President Mohsen Mansouri and on state television. First Vice President Mohammad Mokhber is expected to take over as president.

State media reported that images from the site showed the U.S.-made Bell 212 helicopter slammed into a mountain peak, although there was no official word on the cause of the crash. The dead also included the governor of East Azerbaijan Province and a senior imam from Tabriz city.

The helicopter went down in Varzeqan region north of Tabriz, state news agency IRNA reported, as Raisi returned from an official visit to the border with Azerbaijan in Iran's northwest.

Raisi, 63, was elected president 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.

Iranian Supreme Leader Ayatollah Ali Khamenei, who holds ultimate power with a final say on foreign policy and Iran's nuclear programme, had earlier sought to reassure Iranians, saying there would be no disruption to state affairs.

Messages of condolences came from Iran's regional neighbours including the leaders of India, Iraq and Pakistan, as well as the European Union and Russia.

Iran-backed militant group Hamas, fighting Israeli forces in Gaza with Tehran's support, issued a statement expressing sympathy to the Iranian people for "this immense loss."

Lebanon's Iran-backed Hezbollah group and the Houthi rebels in Yemen also issued statements praising Raisi and mourning his death.

PRAYERS, SEARCHES

Rescue teams fought blizzards and difficult terrain through the night to reach the wreckage in the early hours of Monday.

“With the discovery of the crash site, no signs of life have been detected among the helicopter's passengers,” the head of Iran’s Red Crescent, Pirhossein Kolivand, told state TV.

Earlier, the national broadcaster had stopped all regular programming to show prayers being held for Raisi across the country.

Video showed a rescue team, wearing bright jackets and head torches, huddled around a GPS device as they searched a pitch-black mountainside on foot in a blizzard.

Several countries had earlier expressed concern and offered assistance.

The White House said U.S. President Joe Biden had been briefed on reports about the crash. China said it was deeply concerned. The European Union offered emergency satellite mapping technology.

HARDLINER, POSSIBLE SUCCESSOR TO KHAMENEI

The crash comes at a time of growing dissent within Iran over an array of political, social and economic crises. Iran's clerical rulers face international pressure over Tehran's disputed nuclear programme and its deepening military ties with Russia during the war in Ukraine.

Since Iran's ally Hamas attacked Israel on Oct. 7, provoking Israel's assault on Gaza, conflagrations involving Iran-aligned groups have erupted throughout the Middle East.

In Iran's dual political system, split between the clerical establishment and the government, it is Raisi's 85-year-old mentor Khamenei, supreme leader since 1989, who holds decision-making power on all major policies.

For years many have seen Raisi as a strong contender to succeed Khamenei, who has endorsed Raisi's main policies. Raisi's victory in a closely managed election in 2021 brought all branches of power under the control of hardliners, after eight years when the presidency had been held by pragmatist Hassan Rouhani and a nuclear deal negotiated with powers including Washington.

However, Raisi's standing may have been dented by widespread protests against clerical rule and a failure to turn around Iran's economy, hamstrung by Western sanctions.

Raisi had been at the Azerbaijani border on Sunday to inaugurate the Qiz-Qalasi Dam, a joint project. Azerbaijan's President Ilham Aliyev, who said he had bid a "friendly farewell" to Raisi earlier in the day, offered assistance in the rescue.