BEIRUT (Reuters) - A big explosion shook the central Damascus district of Mazraa on Thursday, residents said, and Syrian state media blamed what it said was a suicide bombing on "terrorists" battling President Bashar al-Assad.

Syrian television broadcast footage of at least four bodies strewn along a main street and firefighters dousing the charred remains of dozens of burning vehicles. Black smoke billowed into the sky.

It said casualties included children at a nearby school in the residential district of the capital. Debris was spread over a wide area.

The Syrian Observatory for Human Rights, a Britain-based group which monitors violence in the country, said a car bomb had detonated near a building of the ruling Baath Party. It said cars 300 meters away from the blast were badly damaged.

Activists reported at least two further blasts in the city after the Mazraa explosion, but there were no immediate details.

(Editing by Tom Pfeiffer)