video transcript

A tour of the remains of a building destroyed in Aleppo. Residents rummage through wreckage after an airstrike took down a residential building in Syria's largest city. At least two girls were killed in the strike. (SOUNDBITE) (English) UNIDENTIFIED LOCAL RESIDENT SAYING: "Two big bombs -- big bomb crashed the building and as you see, the building is destroyed completely." People continue to search for signs of life. Government forces have increasingly used air power to block lightly armed insurgents in Aleppo. Aleppo has been the theater for some of the heaviest fighting in the battle for control of the country. Rebels hold several districts and have tried to push back against an army counter-offensive. The UN says that about 170,000 have have fled the country -- for some nothing has been left behind.