Iran’s supreme leader has presided over a funeral for the country’s late president, foreign minister and others killed in a helicopter crash on Sunday.

Ayatollah Ali Khamenei led prayers at Tehran University, where caskets carrying the dead were draped in Iranian flags.

President Ebrahim Raisi died alongside Foreign Minister Hossein Amir-Abdollahian and six others in a helicopter crash near the border with Azerbaijan.

Authorities had warned against demonstrations against the funeral procession and insults posted online.

“Oh Allah, we didn’t see anything but good from him,” Ayatollah Khamenei said in the standard prayer for the dead in Arabic.

Iran’s acting president, Mohammad Mokhber, stood nearby and openly wept during the service.

People then carried the coffins out on their shoulders, with chants of “Death to America” heard outside.

They loaded them onto a trailer for a procession through downtown Tehran to Azadi Square, where Raisi gave speeches in the past.

In attendance were top leaders of Iran’s paramilitary Revolutionary Guard, one of the country’s major power centres.

Also on hand was Ismail Haniyeh of Hamas, the militant group that Iran has armed and supported during the ongoing Israel-Hamas war.

Haniyeh is widely considered Hamas's overall leader and has been a prominent member of the movement since 1980. The US Department of State designated him a terrorist in 2018.

“I come in the name of the Palestinian people, in the name of the resistance factions of Gaza...to express our condolences,” Haniyeh said.

He also described meeting Raisi in Tehran during Ramadan, the holy Muslim fasting month.

He said he heard the president say that "the Palestinian issue" remains the key one of the Muslim world, which "must fulfil their obligations to the Palestinians to liberate their land".

He also claimed that Raisi called Hamas' October 7 attack in Israel, which saw 1,200 people killed and 250 others taken hostage, an "earthquake in the heart of the Zionist entity".

Also expected to attend services in Tehran were Pakistan’s Prime Minister Shehbaz Sharif and a delegation from the Taliban of Afghanistan, which included their Foreign Minister Amir Khan Mutaqqi.

Iran’s theocracy declared five days of mourning over Sunday’s crash, encouraging people to attend the public mourning sessions.

Typically, government employees and schoolchildren attend such events en masse, while others take part out of patriotism, curiosity or to witness historic events.

For Iran’s Shiite theocracy, mass demonstrations have been crucial to demonstrating the legitimacy of their leadership since millions thronged the streets of Tehran to welcome Grand Ayatollah Ruhollah Khomeini in 1979 during the Islamic Revolution, and also attended his funeral 10 years later.

An estimated one million turned out in 2020 for processions for the late Revolutionary Guard General Qasem Soleimani, who was killed in a US drone strike in Baghdad.

Across the capital, large banners were raised hailing Raisi as "the martyr of service", while others bade "farewell to the servant of the disadvantaged".

Some residents in Tehran received texts urging them to attend Wednesday's ceremonies, the AFP news agency reported.

Footage carried by state TV showed streets filled with mourners, many of whom were carrying pictures of Raisi or the Iranian flag.

Funeral rites for the men began on Tuesday in the city of Tabriz and the Shiite clerical centre of Qom, where thousands of mourners attended ceremonies.

After Wednesday's procession in the capital, Raisi's remains will be moved to South Khorasan province, before being transferred to his home city of Mashhad in the northeast.

He will then be buried on Thursday evening in the city after funeral rites at the Imam Reza shrine.

Raisi, a hardline cleric, was a highly divisive figure in Iran. In the 1980s, he oversaw the execution of scores of opposition activists while working as a prosecutor.

He unleashed a brutal crackdown against demonstrators angered by the killing of 22-year-old Mahsa Amini in 2022. She died three days after she was detained by morality police in the capital for allegedly violating Iran's strict rules requiring women to cover their hair with a hijab, or headscarf.

But his ultra-conservative outlook won favour with supporters of the regime, and Raisi was viewed as a possible successor to Ayatollah Khamenei.