A car bomb exploded in central Damascus, causing casualties, state television said on Monday.
A resident in Damascus, who described the explosion as the biggest she had heard in the capital, said large plumes of black smoke were rising from the area.
State television said the explosion occurred near a school in Sabaa Bahrat, an area that also houses the Central Bank, the Ministry of Finance and is considered the capital's main business district.
Residents and opposition activists reported hearing many ambulance sirens and gunfire in the area. State television said shots were fired in the air to open the street to ambulances.
Syrian rebels, who have been fighting for nearly two years to oust President Bashar al-Assad, have pushed into areas surrounding the heart of the capital and have increased mortar round and car bomb attacks in government-held Damascus.