Iran's Supreme Leader Ayatollah Ali Khamenei named a new acting head of government on Monday, as the country prepared to hold a memorial service for president Ebrahim Raisi who was killed in a helicopter crash.
Raisi and foreign minister Hossein Amirabdollahian were among nine who died when their helicopter crashed in Iran's mountainous north-west during bad weather.
Khamenei described Raisi as "tireless" and said Iranians had lost a "valuable and sincere person."
He ordered five days of national mourning.
New elections to be held
Khamenei named First Vice President Mohammad Mokhber as acting president and tasked him with organizing elections within 50 days. Deputy Foreign Minister Ali Bagheri, the top negotiator in the nuclear talks with the West, was appointed acting foreign minister.
A presidential election could take place as early as the end of June, the Iranian Students' News Agency (ISNA) reported.
June 28 has been put forward as a possible date, with registration of candidates commencing on May 28, ISNA said, citing a spokesman for the electoral authority.
Memorial ceremonies planned for Tuesday
Memorial ceremonies for both Raisi and Amirabdollahian are planned for Tuesday.
News agency Tasnim reported that a ceremony is planned in the north-west in the provincial capital of Tabriz in the morning, followed by a ceremony in the religious stronghold and pilgrimage city of Qom.
The date for the funerals of the two statesmen has not yet been announced. Raisi is to be buried in his hometown of Mashhad.
Reactions to Raisi's death pour in
Russian President Vladimir Putin called Raisi a "true friend" who was admired at home and abroad, while Chinese President Xi Jinping said Raisi's "unfortunate death is a great loss to the Iranian people and the Chinese people have also lost a good friend."
The United States - seen as an arch-enemy by Tehran - expressed its "official condolences."
"As Iran selects a new president, we reaffirm our support for the Iranian people and their struggle for human rights and fundamental freedoms," the State Department said in a written statement.
European Council President Charles Michel offered his sympathy on behalf of the European Union. Italian Prime Minister Giorgia Meloni also expressed her solidarity.
Leader with controversial past
During Raisi's time in office, Iran deepened its economic and military cooperation with China and Russia. Relations with the West deteriorated due to the dispute over Iran's nuclear programme and Tehran's support for Russia's war on Ukraine.
The West also accused the Iranian leadership of human rights violations, especially in the wake of the death of Kurdish woman Mahsa Amini while in the custody of the religious police. Her death sparked mass street protests that were brutally crushed by security forces in 2022.
Despite the title of president Raisi was only number two in the country's power structure as Khamenei functions as the head of state and has the final say in all strategic matters. He is also commander-in-chief of Iran's armed forces.
Experts had tipped Raisi as a possible successor to Khamenei, who turned 85 in April.
While government supporters mourned the loss of the statesmen, many Iranians expressed their glee on social media.
Raisi's government has been criticized for years for its arch-conservative values, the suppression of civil rights and the severe economic crisis in Iran.
No explanation yet for what caused crash
On Monday morning, state news agency IRNA published images taken by a drone showing the debris of the charred helicopter on a steep slope in the middle of the forest.
Raisi and Amirabdollahian were travelling back from a meeting with the president of neighbouring Azerbaijan, Ilham Aliyev, when their helicopter disappeared from radar in dense fog on Sunday afternoon.
The Iranians had helped to inaugurate a dam in Azerbaijan that was jointly built by both countries. The entourage then made its way back to Iran in a total of three helicopters. But while the other two helicopters arrived safely, the president's never returned.
The country's army chief has called for a thorough investigation into the cause of the helicopter crash.
According to a report by ISNA, General Mohammed Bagheri has put together a highly experienced technical team in the Defence Ministry to investigate.
Speculation arose as to whether the crash was indeed due to bad weather, or a technical defect in the helicopter or even sabotage. Iranian officials have yet to give a definite cause.