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.