Iranian Reformist Mirhossein Mousavi called on Wednesday for a day of mourning for those killed in clashes set off by a disputed presidential election as tens of thousands protested for the fifth straight day, Reuters reported.
(Editors' note: Reuters and other foreign media are subject to Iranian restrictions on their ability to report, film or take pictures in Tehran.)
Supporters of defeated candidate Mousavi defied authorities in Tehran to demonstrate against the victory of hardline President Mahmoud Ahmadinejad in Friday's poll, which caused the worst unrest since the 1979 Islamic revolution.
Street battles in Tehran killed at least seven people on Monday, according to state media. Other protests have flared up in cities across Iran.
"A number of our countrymen were wounded or martyred," Mousavi said, calling Thursday's day of mourning.
"I ask the people to express their solidarity with the families ... by coming together in mosques or taking part in peaceful demonstrations," Mousavi said on his website.
Bloodshed, mass protests, arrests and a media crackdown have focused world attention on the fifth-biggest oil exporter which is locked in a row over its nuclear program with the West.
After Mousavi's web message, his supporters poured into Tehran's Haft-e Tir Square, ignoring an Interior Ministry warning, witnesses said. They were mostly dressed in black with wristbands and headbands in Mousavi's green campaign colors.
Most of the protesters, some holding pictures of him as well as green balloons, were silent and making victory signs. One young woman held a picture of one of those killed during post-election violence.
The mass protests are a direct challenge to the authorities who have kept a tight grip on dissent since the U.S.-backed shah was overthrown in 1979 after months of protest.