The explosion occurred near al-Sahil Mosque in Rankus, some 30 kilometers north of Damascus, soon after Friday Prayers.
It was not immediately clear who carried out the deadly attack.
The Syrian government has not commented on the bombing.
The blast happened amid growing tension between militant groups over gaining more share of powers in the controlled areas in several Syrian cities.
The Syrian opposition in exile said in a recent statement that the radical militants were trying to "steal the (alleged) revolution".
No group has already accepted the responsibility of this attack.
But it seems that foreign backed militant groups have committed such heinous attack in retaliation of their continuous defeats imposed by army troops in several cities within recent days.
NJF/NJF