Syria's air force struck Sbeineh south of Damascus on Saturday, as loyalists pressed a fierce bid to crush rebel bastions around the capital, a monitoring group said.
"Warplanes struck areas of Sbeineh... as regime troops shelled the town," said the Syrian Observatory for Human Rights.
Rebels on the capital's southern front were battling government troops backed by both pro-regime militias and fighters from the Lebanese Shiite movement.
"The strike was part of the regime's offensive against rebel areas in and around southern Damascus," Observatory director Rami Abdel Rahman told AFP.
There has been a marked escalation in recent days along Damascus' southern belt, which has been under a suffocating siege for months, giving rise to widespread malnutrition especially among children.
In eastern Damascus, battles raged between rebels and troops, while loyalists also pressed an advance in Barzeh, north of the capital, the Observatory said.
The regime has for months been trying to secure the capital, which is surrounded by rebel positions.
Elsewhere, warplanes struck Mahin, a town in the central province of Homs, where rebels have for two weeks been battling to take over massive weapons warehouses.
The battles in Homs have left scores of fighters on both sides dead, said the Observatory, which relies on a network of sources on the ground.
The Syria conflict was sparked by a regime crackdown on democracy protests. It is estimated to have killed more than 120,000 people and forced millions more to flee their homes.