Thousands of defiant protesters clashed with police in the streets of Tehran on Saturday in protest of last week's presidential election. The unrest left 19 people dead, hospital sources said. Unconfirmed reports put the death toll as high as 150 on the seventh day of post-election demontrations, CNN reported.

Police were using tear gas, clubs and water cannon as they tried to disperse the demonstrators.

A stream of videos posted on social networking Web sites appeared to show demonstrators who had been shot.

One video showed a woman trying to protect a man being beaten and kicked by protesters. A motorcycle lies on its side nearby, and another is in flames.

The protests were held in open defiance of warnings issued Friday by Iran's supreme leader, Ayatollah Ali Khamenei, and the Islamic Republic Security Council. They had said protest organizers -- specifically Moussavi -- would be held accountable if the protests led to bloodshed.