Syrian army defectors have attacked a major military base near Damascus, a Syrian opposition group says.
Parts of the Air Force Intelligence building in Harasta were destroyed in the overnight attack, said the Syrian Revolution General Commission.
The Free Syrian Army used rockets and machine-guns, it said, in its highest-profile attack since protests began.
It comes as the Arab League prepares to discuss its response to the crackdown on anti-government unrest in Syria.
The Syrian government has severely restricted access for foreign journalists, and reports of violence are extremely difficult to verify.
The UN says more than 3,500 people have died since protests started in March. The Syrian authorities blame the violence on armed gangs and militants.