A decorated truck moved slowly through the crowd in Tehran. Flag-draped coffins stood on the truck bed, and people dressed in black crowded below.
In the sea of people, Iranian flags waved side by side with signs written by hand. "We will kill Trump," several read.
In Tehran's Imam Hossein Square, the day began with the hanging of an effigy of the American president, according to state-run Iranian media.
"We are not here to say goodbye, we are here for revenge. And we will take revenge," Fatima Hassan, one of the mourners in the capital, told the AP news agency.
Fell out of the coffin
Along the route of the procession, crowds were sprayed with water in an attempt to ease the heat, according to images published by, among others, the state-run Iranian news agency Fars.
The authorities hoped to avoid the chaos that characterised the funeral of Khamenei's predecessor Ruhollah Khomeini in 1989. Then about ten people died and more than 10,000 were injured in crowds that attracted several million people.
The ayatollah's body also fell out of the coffin when the crowds stormed the hearse.
The successor is not visible.
The coffins of Ali Khamenei and four family members, all killed in US-Israeli attacks on the first day of the war, were then transported via Tehran's Mehrabad airport. Further ceremonies await in Qom and in Iraq's Najaf and Karbala, before Khamenei is finally laid to rest in his hometown of Mashhad on Thursday.
Ahead of Monday's procession, the Supreme Leader's coffin had lain on the parade ground in the Grand Mosalla mosque complex in Tehran for two days.
On Sunday, three of the ayatollah's sons made a rare public appearance, but Mojtaba Khamenei, who succeeded his father as the country's supreme leader, is still conspicuous by his absence.
He has not been seen in public since his family members were killed. He may have been injured in the same attack, but it is not known how severe his injuries are.
