Assad troops pounded a freedom fghters' hideout near Damascus killing at least three people on Wednesday.
Residents of Douma, about 13 km from Damascus, reported heavy shelling since dawn and bursts of gunfire in the town.
Freedom fighters seeking to overthrow the Assad's regime have apparently sought refuge in Douma.
In Damascus itself, clashes erupted briefly between an Alawite security patrol and freedom fighters in the neighborhood of Maisat, but there were no casualties.
In the eastern province of Deir Ezzor, Assad' security gangs carried out raids and arrests of peaceful Muslims in the villages of Al-Safira and Al-Hisan.
Two members of Assad's security forces were eliminated after midnight in the Jura district of Deir Ezzor, the scene of heavy shooting and explosions.
On Tuesday evening, a man was killed in the town of Soura in Deir Ezzor after Assad's gunmen attacked his car, leaving his daughter wounded.
One civilian was killed and three wounded in heavy machinegun fire by Assad's regime forces in Tell Ain al-Hamra, near the town of Jisr al-Shughur in the northwest province of Idlib, on Wednesday.
Jisr al-Shughur is near the Turkish border and has had a significant presence of fredom fighters since the beginning of the uprising.
Rural villages east of Jisr al-Shughur and the town itself came under mortar attack by Assad's security forces.
In the same province, in the village of Ahsem, an Alawite army checkpoint was targeted by an explosion followed by gunfire.
Shots were also heard early on Wednesday in several districts of the central Syrian city of Homs, a stronghold of opposition groups.
Nearly 12,000 Muslims, mostly civilians, have been killed in Syria by Assad's gangs since an anti-regime uprising erupted in mid-March last year.