A sniper killed three men Sunday in Lebanon's northern city of Tripoli, bringing to nine the toll in 24 hours of sectarian clashes linked to the conflict in neighbouring Syria.
A security source said the three men were in a truck when they were shot dead.
Lebanese soldiers deployed in the area to try to retrieve the bodies of the unidentified men.
Their deaths came after a day of fierce clashes that lasted into the night, leaving 33 wounded by fighting that included the use of rocket-propelled grenades.
The fighting pits residents of the city's Alawite Jabal Mohsen district against Sunni residents of the neighbouring Bab el-Tebbaneh.
The source said fires had broken out in buildings along the dividing line between the neighbourhoods as a result of the fierce clashes.
Tensions between the neighbouring areas date back to Lebanon's 1975-1990 civil war but have been exacerbated by the conflict across the border in Syria, where Alawite President Bashar al-Assad is battling a Sunni-led uprising.
The Lebanese army remained deployed in the coastal city in the north of the country on Sunday, responding to sporadic sniper fire.
A military source said soldiers had arrested four suspects, confiscating their weapons and turning them over for questioning.
At least eight soldiers were among those wounded in Saturday's clashes, and the dead included 15-year-old Omar al-Haswani, who was killed inside the Luqman school, near Bab el-Tebbaneh.
During the height of Saturday's violence, soldiers moved into the school to evacuate students in military vehicles.
The others killed included three residents of Bab el-Tebbeneh, as well as a Syrian and a Palestinian, the security source said.
Tensions have been running high in Tripoli since Thursday, when residents of Jabal Mohsen began flying Syrian flags to demonstrate their support for the Assad regime.
In response, residents of neighbouring Bab el-Tebbaneh raised the flag favoured by rebels seeking the ouster of Assad.
The same day, gunmen shot and wounded four Alawite workers in the city, prompting condemnation and demonstrations by Alawite residents.