People in Damascus have held a vigil for the 55 people killed in Thursday’s car bombings.
More than 370 others were injured by the blasts, in what is the deadliest attacks on the Syrian capital since the uprising began over a year ago.
Government and opposition forces agreed to a ceasefire last month, but it is unsure if either side was involved in the car bombings as no one has claimed responsibility.
Speaking about whether terrorists were to blame, US Secretary of Defence Leon Panetta said: “We do have intelligence that indicates that there is an al Qaeda presence in Syria. But frankly, we don’t have very good intelligence as to just exactly what their activities are. And that’s the reason we can’t really indicate specifically what they are or not doing.”
Bombs were detonated in two cars almost simultaneously at eight o’clock local time on Thursday morning.
One was parked close to a secret police agency building.
Syrian authorities are blaming foreign-backed terrorism and have called on the UN Security Council to take measures against these countries or groups.