Syria's state media are reporting a large explosion in the center of the capital, Damascus.
Police say a car bomb exploded on February 21 near the headquarters of Syria’s ruling Ba'ath party and the Russian embassy.
The Syrian Foreign Ministry blamed the bombing on "terrorist" groups linked to the extremist Al-Qaeda network.
State television said the blast killed at least 53 people and wounded more than 200.
The Russian embassy reported some of its windows were broken by the explosion.
There were also reports of two mortars being fired at a military headquarters in Damascus.
The opposition Syrian Observatory for Human Rights said at least 13 people, including 10 soldiers, were killed in that attack.
Based on reporting by Reuters, AFP, AP, and Interfax