Explosion near Damascus market kills at least four
The SANA news agency said the "terrorist explosion" had also wounded 19 people.
The Syrian Observatory for Human Rights monitoring group said it occurred close to Hamidiyeh market, killing seven and wounding at least 20.
A Nusra Front Twitter feed said one of the group's members blew himself up inside a bus at the market. It posted a photo of a man it said was the bomber and another of the wrecked vehicle. Reuters could not immediately verify the images.
Nusra Front has been battling Syrian government forces as well as other insurgent groups in Syria. While fighting has raged on the outskirts of Damascus, attacks in the centre are relatively rare.
(Reporting by Sylvia Westall in Beirut and Omar Fahmy in Cairo; editing by Andrew Heavens and Jason Neely)