Activists say Syrian regime forces have shelled rebel strongholds near Damascus International Airport, AP reported.

There were no reports of casualties from the shelling, which targeted the towns of Beit Sahm and Shebaa near the main airport road south of the capital.

The Britain-based Syrian Observatory for Human Rights and the Local Coordination Committees also reported clashes in rebel strongholds of Daraya and Moadamiyeh, southwest of Damascus.

Friday February 22 violence follows a particularly bloody day in the Syrian capital, which was struck by three car bombings, including a suicide blast that killed at least 53 people.

Recent rebel advances in the Damascus suburbs, combined with the bombings and three straight days of mortar attacks, mark the most sustained challenge of the civil war for control of the seat of President Bashar Assad's power.