The Lebanese army deployed Tuesday in sectors of Tripoli affected by clashes, calming the area after three days of sectarian fighting that killed nine people, an AFP correspondent said.
Troops entered Syria Street, the frontline of fighting between the majority Sunni Muslim district of Bab el-Tebbaneh, and Jabal Mohsen, whose residents are mostly Alawite, at around 6am.
Bab al-Tebbaneh sits opposite Jabal Mohsen, where the majority of residents are from the minority Alawite sect, an offshoot of Shiite Islam to which Syrian President Bashar al-Assad belongs.
Tension between the two neighbourhoods in the north Lebanon city had been simmering for years but burst into the open several times after a revolt in Syria against Assad's regime broke out in March 2011.
Lebanese army units started positioning themselves in the two districts late Monday evening and completed their deployment on Tuesday morning in all neighbourhoods affected by clashes.
"Thank God, the army has entered and we have peace now," Bab el-Tebbaneh resident Ahmed Jaber told AFP by telephone.
"Some of the people who had fled the area have started to return, but most are still scared because fighting has resumed in the past even after the army has been deployed," he added.
Meanwhile, a clean-up operation began in Bab el-Tebbaneh, with bulldozers removing both roadblocks set up by armed gunmen, and unexploded munitions.
Lebanese electricity company teams also started work in the beleaguered district, after violent clashes left residents of the neighbourhood without power.
Battles first erupted on Saturday between residents of the rival neighbourhoods after security forces arrested Shadi al-Mawlawi, a Sunni Islamist, on charges of belonging to a terrorist organisation.
A total of nine people, including a soldier hit by sniper fire, died in the port city and dozens were wounded in the fighting.