Some 18 civilians were killed across Daraa and Homs in aerial attacks waged by Syrian government forces, said the Syrian Observatory for Human Rights on Sunday.
A family of 12, including two Syrian women, were killed by bombardment involving explosive barrels in the city of Busra Al-Sham in southern Syria's Daraa.
The death toll is expected to increase as there are also several injuries in critical condition.
In Homs, a Syrian family of six, including three children, was killed and at least five others wounded as a result of three air raids on areas in Damascus Countryside.