Three children from one family were among five people killed in an air strike Monday on a building in a central district of the embattled northern city of Aleppo, the Syrian Observatory for Human Rights said.
"Three children from the same family were killed when their building collapsed in Maadi district, which is located in the Old City of Aleppo, 600 metres (yards) from the citadel," the watchdog's Rami Abdel Rahman told AFP.
"There are still people buried under the rubble," he added.
A video posted to YouTube by activists in Maadi showed a mountain of rubble, all that remains of a flattened building, with the sides of adjacent high-rises also devastated.
In another video, some 15 men can be seen trying to clear away slabs of debris to free trapped residents. The voice-over says "whole families" lived in the building that had been hit in an air strike.
AFP is unable to authenticate these videos independently because of restrictions imposed on foreign media by the Syrian authorities.