Syrian troops on Tuesday pressed an assault on rebel strongholds in the Turkish border region, as the opposition urged foreign military intervention after dozens of women and children were killed in Homs.
The Britain-based Syrian Observatory for Human Rights said Syrian forces used heavy machineguns to rake the town of El-Baraa in the Jabal al-Zawiya region, a rebel bastion in the northwestern Idlib province.
The observatory said armed rebels had hit back before dawn with an attack on a military checkpoint in the town of Maaret al-Numan in which at least 10 Syrian soldiers were killed.
In Khan Sheikhun, another rebel bastion in Idlib, gunmen attacked troops in heavy military vehicles, damaging two of them and seizing others, the observatory said.
It also reported clashes in Deir Ezzor, eastern Syria, in Aleppo, to the north, and in Daraa in the south.
Dozens of people have been killed since last week in on-off army shelling of Idlib city, which is now partly controlled by the regime, and in violence across the province.
On the political front, diplomats in New York said President Bashar al-Assad has until Tuesday to give a response to peace proposals made by UN-Arab League envoy Kofi Annan, who held two rounds of talks with the Syrian leader over the weekend.
Annan said on leaving Damascus that he had made "concrete proposals" to Assad on ending the killing in Syria and securing humanitarian access to protest cities.