The London-based Syrian Observatory for Human Rights says the three soldiers and one civilian were killed Tuesday in fighting in the region of Jabal Al-Zawiya.
Activists also reported clashes elsewhere.
The Local Coordination Committees, an activist network, said defectors attacked an army checkpoint in the southern village of Dael, wounding one officer.
Syria-based rights activist Mustafa Osso said government troops also were conducting military operations in the central town of Talbiseh.
Syria’s six-month opposition movement has focused on peaceful demonstrations, although recently there have been reports of protesters taking up arms to defend themselves against military attacks.