Syrian government forces heavily shelled the central town of Morek in an attempt to wrest it from rebels, activists said on Thursday.
Military helicopters dropped barrels packed with explosives on the city overnight, said the Local Coordination Committees. More than 20 bombs were dropped by aircraft on the town on Wednesday, reported the British-based Syrian Observatory for Human Rights, AP reported.
Morek is one of three towns that lie on a strategic highway linking central and northern Syria. Rebels linked mostly to Islamic groups have been holding the town for the past four months.
Forces loyal to President Bashar Assad appear to be trying to seize Morek to supply the Wadi Deif military base further north.
The Observatory said at least 15 people, including four civilians, were killed Wednesday in the fighting.
Over the past year, Assad's forces have been steadily seizing territory from the rebels.