TRIPOLI, Lebanon (Reuters) -- At lease six people were wounded in a second night of sectarian fighting in Lebanon's port city of Tripoli on Thursday, residents said, the latest sign of violence fueled by the civil war in neighboring Syria.

The sounds of machine guns and rocket propelled grenades rocked neighboring districts that are home to communities linked to both sides of the Syrian conflict.

One area is dominated by Lebanese Sunni Muslims, who support the Sunni-led uprising against Syrian President Bashar Assad, and the other is an enclave of Lebanese Alawites, the same Shi'ite Muslim offshoot to which the Syrian leader belongs.

Tensions over the two-year civil war in Syria have frequently led to street fighting in Tripoli. On Wednesday night, one man was shot dead and at least 20 were wounded in clashes there.

A Lebanese soldier was wounded in Thursday's clashes, said residents. Troops had deployed in the area earlier in the week to try to maintain calm in the area.

Another of the wounded was in critical condition, a medical source said.

The Syrian conflict has also spilled over into the Lebanese capital Beirut and other areas -- and there have been frequent clashes in border regions.