A basement becomes a battlefield in Damascus.
The video which can not be independently verified appears to show rebel forces taking aim at government forces.
Government troops return fire.
One man carries a wounded rebel away from the building.
Others fortify positions as they take up arms for another attack.
The fighting illustrates the volatile situation in Syria as a team of chemical weapons experts start the process of eliminating Syria's chemical weapons stockpile, with inspections expected to begin next week.
More footage appears to show rebel forces launching a rocket at a checkpoint in southwestern Syria. In the aftermath, a man can be heard saying two people are trying to escape.
Rights groups say more than 1,000 people are killed a week in Syria -- in a country where the death toll already tops 100,000.
