Under fire in Damascus

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.