TEHRAN: Defeated Iranian presidential candidate Mir Hossein Mousavi appeared in public on Monday for the first time since the election that has divided the nation, joining thousands of supporters who defied a ban to stage a mass rally in Tehran.

Mousavi turned up in a car at the opposition march to protest at what the moderate wartime premier has branded a rigged “charade,” on the third day of public demonstrations following President Mahmoud Ahmadinejad’s landslide win.

“Mousavi we support you! We will die but retrieve our votes!” shouted the crowds of thousands, young and old, who poured into central Tehran in defiance of an interior ministry ban on the march.

Iran’s supreme leader has ordered a top regime body to look into the complaints raised by the moderate Mousavi, as Iran faced a growing international backlash over the validity of the election and the subsequent crackdown on opposition protests.

Ahmadinejad has defended the results of an election that gave the combative hardline another four years in power, denting Western hopes of a change in domestic and foreign policy of the oil-rich Shiite-dominated nation. As riot police looked on, demonstrators, some wearing the green of Mousavi’s campaign colour, streamed into central Tehran despite the ban, raising the possibility of tense confrontations.

“No authorisation for a march or gathering has been issued and any kind of gathering or march is illegal,” an interior ministry spokesman said.

State television said supreme leader Ayatollah Ali Khamenei had told Mousavi to pursue his complaints against the most hotly-disputed election in the Islamic republic through legal and peaceful means, state television reported.

The former wartime premier lodged a formal appeal on Sunday for the cancellation of the results, which stoked the worst unrest in the Islamic republic for a decade.

Former president Mohammad Khatami, a key Mousavi backer who was succeeded by Ahmadinejad, wants the results of the vote cancelled and a new election held, his brother said.

Khamenei said the 12-member Guardians Council had been advised to “precisely examine” Mousavi’s letter. It would announce its decision in 10 days. European governments complained about the tactics used against protesters and added their voices to US doubt over the election outcome, with the EU calling on Tehran to launch a probe into the results.