Pro-government television stations showed pictures of damaged buildings and vehicles and said there were an as yet undetermined number of casualties.
Security agencies in several Syrian cities have been targeted by a wave of explosions since late last year as violence has escalated with government crackdowns on protests.
The latest bombing follows a blast targeting an intelligence building in Damascus May 10.
UN Secretary-General Ban Ki-moon said on May 17 he believed that "alarmingly and surprisingly," Al-Qaeda must have been behind the May 10 attack in the Syrian capital.
The waves of bombings are raising fears that Al-Qaeda-linked Islamist militants, possibly including fighters from neighboring Iraq, have made strong inroads into Syria's rebel movement.
