The march began hours after Iran’s supreme leader Ayatollah Ali Khamenei called for an inquiry into Opposition claims that the election was rigged in favour of President Mahmoud Ahmadinejad.

Khamenei’s call — announced every 15 minutes on Iranian state radio throughout the day — was the first sign that Iran’s top leadership might be rethinking its position on the election. Khamenei had said on Saturday that the election results showing a landslide victory for Ahmadinejad were fair.

As evening fell, reports of gunfire began to emerge, but for most part, the silent march was a deliberate and striking contrast with the chaos of the past few days. Associated Press reported that gunmen fired at agitators at the march, killing at least one person. An Associated Press photographer saw one person shot dead and several others who appear seriously wounded in Tehran’s Azadi Square. The shooting came from a compound for volunteer militia linked to Iran’s Revolutionary Guard.

A broad river of people — young and old, dressed in traditional Islamic gowns and the latest Western fashions — marched slowly from Revolution Square to Freedom Square for more than three hours, many of them wearing the signature bright green ribbons of Moussavi’s campaign, and holding up their hands in victory signs. When the occasional shout or chant went up, the crowd quickly hushed them, and some held up signs bearing the word “silence”.

Moussavi attended the rally, addressing a sea of supporters from the roof of a car in his first public appearance since the disputed vote. “The vote of the people is more important than Moussavi or any other person,” Agence France-Presse quoted him as saying. “God willing, we will get back our rights.”

The protesters said they would continue, with another major rally planned for Tuesday. But it was too soon to tell whether Khamenei’s decision to launch a probe, or the Government’s decision to let the silent rally proceed unmolested, would change the election results. Many in the crowd said they believed the Government was simply buying time, and hoping the protests would dissipate — as smaller protest movements have in 1999 and 2003.

Reports said that some of Ahmadinejad’s followers paraded outside the British and French Embassies in Tehran following remarks by political leaders in London and Paris casting doubt on the Iranian leadership’s conduct.

Opposition websites reported that security forces raided a dormitory at Tehran University and 15 people were injured. Between 150 and 200 students were arrested overnight, by these accounts, but there was no immediate confirmation of the incident from the authorities.

In Moscow, meanwhile, an official at the Iranian Embassy said that Ahmadinejad had delayed a visit to Russia that was to have started Monday. The meeting, in Yekaterinburg, is of the Shanghai Cooperation Organization that includes Russia, China and four Central Asian countries. He now plans to travel on Tuesday, the official said.