TRIPOLI, Dec. 19 (Xinhua) -- Three people were killed and another was injured after the roof of a residential building collapsed in the Bab al-Jadid area in the Libyan capital Tripoli's Old City, authorities said Friday.

The fatal victims were a mother and her two daughters, while the injured adult was sent to Tripoli Central Hospital for treatment, said the Ambulance and Emergency Service in a Facebook post.

Rescue teams continued searching the rubble, while an investigation has been launched to determine the causes of the collapse. ■