At least 40 people, mostly civilians, have been killed and at least 100 other people wounded by the two suicide car bombs in Damascus, a Syrian government official said.

The attack comes ahead of calls by anti-government activists for fresh protests across the country and a day after an Arab League observer mission arrived to implement a peace initiative to end the country's nine months of violence.

An Al-Qaeda group may have been responsible for the twin car bombings, according to a state media report.

Al Jazeera's Tarek Bazley reports.