TRIPOLI, Lebanon - Lebanese troops deployed in the northern city of Tripoli early on Sunday after fierce clashes between supporters and opponents of Syrian President Bashar Assad in which 13 people were killed, local medics and security sources said.
Residents said relative calm had returned to the city since the soldiers deployed at around 7 a.m. (0400 GMT), after gunmen exchanged heavy machinegun fire and rocket propelled grenades.
Prime Minister Najib Mikati and other Tripoli politicians instructed security forces on Saturday to use an "iron fist" to quell the worst violence to shake Tripoli since the start of an uprising against Assad in neighboring Syria.
The mainly Sunni Muslim protests against Assad have polarized Tripoli, where a small community of Alawites - from the same offshoot of Shi'ite Islam as Assad - have frequently clashed with majority Sunni Muslims who support the uprising.
The latest clashes began after midnight on Friday and continued throughout Saturday until the army deployment.
Gunmen from the Jebel Mohsen district, home to Tripoli's Alawite residents, have fought intermittent skirmishes over the past few weeks with Sunni Muslim fighters in the Bab al-Tabbaneh area.
Saturday's death toll was the highest in a single day in Tripoli, raising fears that Syria's unrest was spilling over into its smaller neighbor.
The Lebanese National News Agency said there was "shelling across both areas heard every five minutes, and snipers targeting civilians".
Residents said those killed included civilians caught in the crossfire and that a Lebanese soldier was among the wounded.
The areas have long-standing grievances separate from the Syrian conflict but the Sunni-led uprising against Assad has caused strife among Lebanon's mixed population, especially in Tripoli, 70 km (43 miles) north of Beirut.
Syria flooded Lebanon with troops early in its 1975-1990 civil war and dominated its neighbor for more than a decade afterwards. It retains significant influence over Lebanon's intelligence apparatus and military, despite having withdrawn troops in 2005.