Fresh amateur video footage posted to the Internet claims to show pro-government agents in civilian clothes breaking up a peaceful sit-in in the Syrian capital on Monday, hauling demonstrators into a van.

The dramatic clip, claimed to have been filmed in Damascus' Arnoos Square, shows crowds of men and women sitting in a street, chanting and clapping their hands. Activists say 250 people turned out for the sit-in during which rally-goers chanted, "The Syrian people are not divided by sectarian issues," "Stop the gunfire" and "Stop the siege on our cities."

At one point, the crowd gets up and starts marching down a street as curious passersby look on, prompting what are said to be plainclothes security officers to show up at the scene and take action.

Timeline: Uprising in Syria