Large crowds filled Enqelab Square and nearby streets as festivities stretched across a 10-kilometre route through the capital. Participants were also seen treading on a US flag, while an Iranian-made Shahed-136 drone was displayed during the event.

Attendees said the gathering was not only a religious occasion but also an opportunity to demonstrate loyalty to the country's leaders.

"This large crowd that has gathered here has all come out of love for the Amir al-Momenin (Prince of the Believers) and out of love for our leaders - both our martyred leader, and to pledge allegiance to our new leader," said Karimi.

She added: "This immense crowd itself shows that we stand behind our country and behind our leader. We will stand behind this Islamic system until the very end."

Iranian media reported that participants renewed their pledge of allegiance to Supreme Leader Mojtaba Khamenei during celebrations held across the country.

Mohseni, another attendee, said the turnout reflected continued support for Iran's political system.

"The people stand behind this nation, behind their homeland. They defend the leadership and will never abandon it. I hope it always remains this way. We are even willing to sacrifice our lives for them," he said.

According to Iranian media, Eid al-Ghadir events were held in several provinces, although some celebrations were delayed because of high temperatures.

Eid al-Ghadir commemorates the anniversary of Prophet Muhammad appointing Imam Ali ibn Abi Talib as his successor at Ghadir Khumm, according to Shiite belief and several other Islamic traditions. Across Iran , the occasion is marked with religious gatherings, processions and public celebrations.

Hundreds of people gathered at Khomeini's mausoleum, waving Iranian flags and taking part in ceremonies marking the 37th anniversary of his passing. A memorial chair honouring the late leader was also displayed.

During the event, Ahmad Khomeini, the grandson of the founder of the Islamic Republic, referenced recent attacks while recalling his grandfather's views on the United States .

“Imam Khomeini called America the Great Satan. We witnessed this in the explosions at Minab School, in the martyrdom of our children, and in the killing of the father of our Ummah,” he said.

The commemoration also featured a message from Supreme Leader Mojtaba Khamenei, which was read by Mohammad Javad Haj Ali Akbari, a representative of the Supreme Leader.

The message said Iran's enemies were attempting to weaken public resilience and influence decision-making by spreading fear and division.

“In confronting these malicious intentions, everyone must neutralise these plots through steadfastness, awareness, unity, cohesion, mutual trust, and by refusing to echo the enemy’s narrative,” the message said.

Hundreds of thousands of people reportedly travelled from across Iran to attend the ceremony honouring Khomeini, who led the 1979 Islamic Revolution and established the Islamic Republic before his death on June 3, 1989, at the age of 89.

The event took place amid continuing tensions following the Minab school attack, which killed around 170 people, many of them children. Iran blamed the United States and Israel for the strike. Israel said it was unaware of any operations in the area, while US Central Command chief General Brad Cooper stated on May 19 that the school was located inside an active cruise missile base.