Syrian troops bombarded rebel bastions near the capital on Sunday a day after at least 32 civilians including 11 children were killed by air strikes and artillery fire in the Damascus area, a watchdog said.

The Syrian Observatory for Human Rights reported that the children and two women were among the victims of bombardments focused on southwest and northeast Damascus suburbs and outlying towns on Saturday.

Overnight, regime forces battled rebels in the opposition stronghold of Harasta northeast of Damascus and bombarded the town of Moadamiyet al-Sham to the southwest and Bait Saham near the airport road to the southeast, it said.

The Local Coordination Committees, a network of activists on the ground, also reported artillery fire on Sunday on residential neighbourhoods in Moadamiyet al-Sham coming from the direction of Mazzeh military airport.

In the southern province of Daraa, considered the cradle of the rebellion, troops and rebels clashed in the town of Sheikh Maskeen and battled for control of several small border crossings on the regime-controlled border with Jordan.

Syria and Jordan share a 370-kilometre-long (230-mile) border which hundreds of people cross on foot every day to escape the bloody civil war which the Britain-based Observatory says has killed at least 45,000 people.

Two rebels were also reported killed in clashes with troops in the central province of Hama, where a series of blasts also rocked the provincial capital.

In neighbouring Homs province, the army pounded the rebel-controlled area around the Crac des Chevaliers crusader castle, a UNESCO-listed world heritage site.

Dozens of casualties were also reported in Homs city after a fierce regime assault ended in the army seizing the Deir Baalbeh district on Saturday, according to the Observatory.

The watchdog, which gathers its information from a network of activists and medics in civilian and military hospitals, said the final death toll had not yet been documented because of communications difficulties in the area.

One video released by the Syrian Revolution General Commission showed the bodies of nine male victims from Deir Baalbeh lying on the ground, their faces bloody and mutilated. Its authenticity could not be immediately verified.