A car bomb killed at least 20 people and wounded dozens more on Friday when it exploded in Rankus, a town 30 km (20 miles) north of the Syrian capital Damascus, the Syrian Observatory for Human Rights said.
Activists in a nearby town said the blast occurred in front of a mosque soon after Friday prayers. They gave a higher death toll of 37 dead and said more than 100 had been wounded.
One of the activists told Reuters that government forces began shelling the same area soon after the explosion occurred, causing at least one more death.