Hours-long clashes overnight in a Beirut neighbourhood between supporters and opponents of Syrian President Bashar Assad killed one person, prompting Lebanese troops to deploy in the area to calm tensions.
The gunmen - from rival Sunni groups - exchanged gunfire and rocket-propelled-grenades for several hours on the edge Beirut's predominantly Sunni neighbourhood of Tariq Jadideh, the worst fighting in the Lebanese capital in nearly two years. Beirut and its environs have experienced a number of deadly bombings.
The violence was also the latest spillover of the Syrian civil war into its smaller neighbour. Lebanon has been on edge since Assad's troops recently took a key rebel stronghold near the two countries' volatile border.
By dawn, cracks of gunfire and sporadic explosions were still heard around Beirut. Lebanese soldiers in armoured personnel carriers and Humvees fanned out on the edge of the district as scores of gunmen, many of them masked, pulled out from the streets in the morning hours.
Lebanon's Internal Security Forces said one person was killed and 15 were wounded in the fighting. The authorities did not say if the victims were civilians or gunmen.
Shaker Birjawi, head of the pro-Assad Arab Movement Party, said four of his followers were wounded in the fighting. State-run National News Agency said Birjawi's AMP fought against rival Sunni gunmen.
The fighting comes after days of clashes, also related to the civil war next door, killed 25 and wounded more than 160 people in the northern Lebanese city of Tripoli.
Sunday's clashes were the worst in Beirut since May 2012, when Birjawi's gunmen were forced out of Tariq Jadideh.
Syria's crisis, which began in March 2011, has killed more than 140,000 people in Syria so far and has sharply divided the Lebanese.
Also Sunday, a fugitive hardline Sunni cleric appeared in a video for the first time since he and his followers were crushed by the Lebanese army in June in the southern city of Sidon.
Sheik Ahmad al-Assir said in the video dated March 23 that the Lebanese army is dominated by the Shiite militant Hezbollah group and called on Sunni members of the military to stand against what he called "injustice."
"I send a message to every honourable member of the Lebanese army, especially Sunnis, to change (their allegiance) and to end injustice," the bearded cleric said from an unknown location.
The video appeared days after reports that he was killed while fighting with rebels against Syrian forces and Hezbollah fighters who last week captured the town of Yabroud near the Lebanon border. It was not possible to confirm the video's March 23 caption.
"We will not kneel and surrender to you. It is impossible to live with you until your head is crushed," he said to Hezbollah.
Al-Assir has released several audio clips following last year's battles, but this is the first video.