Syrian TV says mortar shells have exploded near the Syrian Army General Command in central Damascus, causing no casualties.
The station said the building was empty because it was under renovation.
The Britain-based activist group Syrian Observatory for Human Rights said two mortars struck near the building on Thursday but did not report casualties.
The attack follows a car bomb attack at a security checkpoint in Damascus that opposition activists say killed at least 32 people and two days of successive mortar strikes on the capital.
On Wednesday, two mortar shells exploded next to a soccer stadium in Damascus, killing one player. The day before, two mortar shells blew up near one of Assad's three palaces in the city, causing only material damage.