AMMAN (Reuters) - A car bomb exploded near a police station in the central Bab Touma district of Damascus on Sunday, witnesses said, and state television said several people were killed.

Ambulances sped to the site and security forces cut off access to the area. Several cars were burnt, the witnesses said.

The explosion took place as President Bashar al-Assad was meeting international envoy Lakhdar Brahimi, who has called for a temporary truce in Syria's civil war.

Damascus residents said Assad's forces shelled several districts on the edge of the Syrian capital overnight. The Syrian Observatory for Human Rights, which monitors violence across the country, said 140 people were killed in Syria on Saturday.

(Reporting by Khaled Yacoub Oweis; Editing by Dominic Evans and Janet Lawrence)