**Rough cut - no reporter narration**
At least 31 people were killed after at least one explosion shook the central Damascus district of Mazraa on Thursday, near a building belonging to Syria's ruling Baath party.
Other activists said at least 40 were killed.
It was reported that casualties included children at a nearby school in the residential district of the capital. Debris was spread over a wide area.
Syrian state media blamed on what it said was a suicide bombing by "terrorists" battling President Bashar al-Assad.
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 metres 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.
Dozens killed in Damascus blast (0:46)
Feb. 21 - Dozens are killed in a large explosion in the central Damascus district of Mazraa. Rough Cut (no reporter narration). ( Transcript )