A series of car bomb explosions, including a suicide attacker who blew himself up after being surrounded by security forces, rocked the Syrian capital on Sunday, killing at least 18 people and wounding more, a monitor said.

The Syrian Observatory for Human Rights said the dead included at least seven pro-regime security personnel and two civilians.

It had not identified the remaining victims.

State media said security forces intercepted the two other car bombs, suggesting they were controlled explosions.

Footage on state TV from the scene of one explosion, along the road to the airport, showed at least two scorched vehicles.

The closed-off street was littered with debris, while security men roamed the area. Footage from Tahreer Square in central Damascus showed the facade of one building badly damaged, and mangled vehicles parked in the small roundabout.

State TV said security forces detected two car bombs at an entrance to the city, and foiled a plot to target crowded areas on first day of work after the long

Muslim holiday that follows Ramadan.

The state news agency SANA said the security forces detonated two car bombs at the airport road intersection.

The Britain-based Syrian Observatory for Human Rights, an opposition-run monitoring group, also reported the three explosions.

Such attacks have been relatively rare in Damascus, the seat of power for President Bashar Assad. Pro-government forces have been fighting to drive rebels from Ain Terma, one of their last strongholds on the eastern outskirts of Damascus.