Activists say clashes between Syrian troops and army defectors have killed at least two people.
Sunday's violence came as the opposition called for a general strike to demand an end the fighting.
The British-based Syrian Observatory for Human Rights says two army armored carriers were burned in the pre-dawn clash in the northwestern town of Kfar Takharim.
The Observatory and the Local Coordination Committees, another activist group, also reported skirmishes in at least two areas in the southern province of Daraa.
The 9-month-old uprising against Syria's authoritarian President Bashar Assad has grown increasingly violent in recent months as once-peaceful protesters take up arms and rebel soldiers fight back against the army. The UN says more than 4,000 people have been killed since March.