Updated

Activists say Syrian government forces are bombing a strategic rebel-held town in the country's north with heavy artillery and airstrikes for the third straight day, killing at least three people.

The Britain-based Syrian Observatory for Human Rights says President Bashar Assad's troops have besieged the town of Saraqeb in Idlib province, pounding it with rockets, tanks and air raids.

The Observatory says at least three people, including two children, died in a single airstrike on Saturday.

The group, which has activists on the ground, says the number of casualties is likely to rise because many people have been buried in the rubble of buildings that collapsed in the shelling.

The town lies along the highway that links Syria's largest city, Aleppo, with the capital, Damascus, the seat of Assad's power.