At least three people were killed in the western Syrian town of Tal Kalakh where shooting continued with more than 20 snipers deployed on the top of the main hospital in the town, activists said Sunday.
Heavy artillery was shelling the town and surrounding villages, dpa reported.
The army has been deployed in and around Tal Kalakh since Saturday, as part of the military operations aimed at quelling protests that began on March 15 demanding the ouster of President Bashar al-Assad.
Human rights groups say more than 775 people have been killed since pro-democracy protests started in Syria in mid-March.
"As Assad diverts attention away towards the Golan, his thugs have surrounded a mosque with 10 families hiding inside," the opposition reform Party of Syria said in reference to a mass protest on the Syrian border with Israel.
"Unconfirmed reports cite the tanks have turned their artillery against the mosque," added the party.
Around 200 security members gathered in the Damir Police Station, in Douma city as security vehicles were driving around.
Anti-government protesters took to the streets in Idlib city to condemn the wave of arrests across Syria.
Human rights groups say more than 8,000 have been jailed or have gone missing in the crackdown on protesters. Hundreds more are believed to have been arrested in recent days.