A man was killed in fighting between Sunni militants and Lebanese troops in the northern city of Tripoli on Thursday, a security official told AFP.
The tense city has seen a week of deadly clashes pitting Sunni militants in the Bab al-Tabbaneh neighbourhood, who support Syria's rebels, against the Alawite gunmen of neighbouring Jabal Mohsen, who back the regime.
The battle ended after the army deployed troops in the strife-torn neighbourhoods -- separated by the aptly named Syria Street -- to put an end to the fighting.
Speaking to AFP on condition of anonymity, the official said Sunni militants opened fire on Jabal Mohsen earlier Thursday, wounding one person.
"Tension then returned to the frontline," the source said, with troops exchanging fire with the Sunni gunmen and killing one person.
In a week of fighting that broke out last Monday, 14 people from both sides were killed.
Clashes between residents of the rival neighbourhoods date back to Lebanon's own civil war in the 1970s and 1980s, but tensions have spiked since the outbreak of Syria's uprising, raising fears the conflict may spill across the border.
Lebanon was dominated by Damascus for 30 years until 2005, and its population is deeply divided into pro- and anti-Assad camps.
The divisions were further aggravated earlier this year when the powerful Shiite movement Hezbollah openly admitted sending fighters to support Assad's troops in Syria.