There are reports in social media sites of clashes between protesters and security forces in Tehran, Iran. Several clashes have been reported on Twitter with claims of one person killed, tens of demonstrators injured and 200 arrested.

According to CNN, tens of thousands of demonstrators marched along Revolution Avenue in downtown Tehran on Monday, protesting the government of Iranian President Mahmoud Ahmadinejad.

The wave of people remained largely silent as they walked toward the capital city's Azadi Square, but then clashed with Iranian security forces that tried to disperse the marchers and divert them from the square.

Security forces in uniform and plain-clothes members of the pro-government Basij militia rushed toward crowds that were chanting "Death to the dictator!" at Imam Hossein Square, the planned starting point of a scheduled rally, a witness said. Several people were hit, while most were chased away, a witness said.

At least 100 security personnel lined the avenue, allowing the march to continue but preventing the marchers from congregating in the square, considered a rallying point by opposition groups.