"A civilian car had stopped at the checkpoint... And a terrorist got out wearing an explosive vest which he detonated," SANA said, adding that seconds later a man who had remained in the car blew it up.
The Syrian Observatory for Human Rights said the bombing targeted a checkpoint manned by a pro-regime militia, just 10 kilometres (six miles) east of Damascus and on the road to the international airport.
On February 1, a blast ripped through a bus carrying Lebanese Shiite pilgrims in the city, killing at least nine people in an attack claimed by Al-Qaeda's Syrian branch.
The Britain-based Observatory also reported that a rocket hit the Adra prison northeast of Damascus today, killing four people and wounding 15.
It did not say if the casualties were prisoners, guards or visitors.