At least 50 other people had been wounded in the fighting between opponents and supporters of Syrian President Bashar Assad, the Lebanese website Naharnet reported.
A tense calm prevailed Monday.
Schools and businesses were closed.
Clashes described as the city's worst in months were in the mostly Sunni neighborhood of Bab al-Tabbaneh, where residents support resistance against Assad's government and the neighborhood of Jabal Mohsen, where many people are members of Assad's Alawite sect, Naharnet reported.
Machine guns, rocket-propelled grenades and mortar shells were used in the fighting.
Lebanese soldiers arrested eight suspected militants and seized weapons in raids Sunday.