Activists say Syrian government forces have intensified a military offensive against rebel strongholds north of the capital Damascus.

The heavy shelling on many fronts appears to be an attempt to cut links between districts under rebel control.

The Britain-based Syrian Observatory for Human Rights, which relies on an extensive network of activists in Syria, said Saturday the shelling of the district of Qaboun has killed three children, including two from the same family, since Friday. They say it also caused structural damage and started fires. Activists from Qaboun posted on Facebook that government forces deployed additional tanks outside the neighborhood, and the bombardment had brought buildings down.

The Observatory said one rebel fighter was killed in nearby Barzeh, where rebels pushed back against a government attempt to storm the neighborhood.