Rocket-propelled grenades, mortars and machineguns have all been used in six days of clashes in the port city, in the deadliest violence to rock the country for years.
Most of the fighting has been between residents of the Sunni district of Bab el-Tebbaneh who support the rebels battling to topple Assad and people in the Alawite area of Jabal Mohsen who back him.
Four people from Bab el-Tebbaneh were reported dead last night, the security source said, including one who died of his wounds. Another three, including a soldier, were killed in Jabal Mohsen.
At least 204 people have also been wounded in the fighting that erupted in Tripoli on May 19, the source told AFP.
Thursday was the bloodiest day with 11 killed.