In neighboring Lebanon, another two people were killed by sniper fire during fighting between rival sects in the northern city of Tripoli, the official state news agency reported. It said that a soldier in the city also died Sunday of his wounds.
At least 10 people have been killed since clashes flared earlier this week, security officials said.
Syria's civil war effectively has spread to Lebanon's second largest city, where it has inflamed tensions between two impoverished Tripoli neighborhoods, home to Assad opponents and supporters.
The Bab Tabbaneh district is largely Sunni Muslim, like Syria's rebels. The other neighborhood Jabal Mohsen mostly has residents of Assad's Alawite sect, an offshoot of Shiite Islam.
The latest round of fighting began four days ago. Tensions had been mounting since Oct. 14, when a Lebanese military prosecutor pressed charges against seven men, at least one of whom was from Jabal Mohsen, for their involvement in twin bombings near two Sunni mosques in Tripoli on Aug. 23 that killed 47 people.
Lebanon shares its northern and eastern border with Syria. Lebanon's Sunni leadership has mostly supported the rebels, while Alawites and Shiites have backed the Assad government. Members of all three sects have gone as fighters to Syria.