Syrian government aircraft targeted a southern town with a series of airstrikes Sunday, killing at least a dozen people including women and children, activists said.

The Local Coordination Committees activist collective and the Syrian Observatory for Human Rights both reported the strikes on Jasim in the southern province of Daraa.

The Local Coordination Committees said the strikes were barrel bombs -- large canisters packed with explosives and metal scraps -- that cause massive damage on impact. It said at least 12 people were killed, including women and children.

The Britain-based Observatory, which relies on a network of activists inside Syria, put the death toll at 19. That figure included five women and one young girl. It said the air raids were carried out by warplanes, not helicopters.

The discrepancy in death tolls could not be immediately reconciled, but casualty figures frequently differ in Syria after such attacks.

Both groups also reported government airstrikes on the nearby town of Nawa, which opposition forces captured earlier this month. There was no immediate word on casualties there.

Syrian rebels have advanced in southern Syria over the past two months, seizing a string of towns from President Bashar Assad's forces. The rebels are working together with Al Qaeda's Syrian branch, known as the Nusra Front, whose battle-hardened fighters have been at the forefront of the clashes.