A deadly battle between Lebanese Sunnis and Shi'ites overnight has prompted warnings of more violence as the country is pushed to breaking point by a financial meltdown and political tensions.
Two people - a 13-year-old Lebanese Sunni boy and a Syrian man - were killed in the Khaldeh area south of the capital in the shoot-out on Thursday night.
Machine guns and rocket-propelled grenades were used in the fighting which witnesses said lasted four hours.
A Sunni Arab tribe to which the boy belonged accused members of the powerful, Iran-backed Shi'ite group Hezbollah of opening fire. Hezbollah categorically denied having anything to do with the incident.
The Lebanese army, which was heavily deployed in the area on Friday, said the problem spiralled out of a row over a poster put up by Shi'ites to commemorate Ashura, the 7th century martyrdom of Imam Hussein.
The army statement said the problem that erupted was between members of the Arab Khaldeh tribes and residents of the area, without identifying them.
The violence triggered a flurry of contacts among Lebanese politicians seeking to contain tensions.
The country is still grappling with the aftermath of the August 4 port blast which killed 180 people and the financial crisis seen as the biggest threat to stability since the 1975-90 civil war.
Mourners chanted "there is no God but God and Hezbollah is the enemy of God" as the boy's body was carried on a stretcher into his grandfather's house at funeral on Friday.
Men in facemasks fired AK-47s in the air.
Divisions between Lebanese Sunnis and Shi'ites opened up after the 2005 assassination of Rafik al-Hariri, the former prime minister. Rifts emerged again after a UN-backed tribunal recently convicted a Hezbollah commander, Salim Ayyash, of conspiracy to kill him.
Hezbollah denies any role in killing Hariri, Lebanon's main Sunni leader at the time of his death.
"The sporadic rise of violence is another sign of the dismantling of the state," said Mustafa Alloush, a Future Movement leader. "I expect that similar or other types of violence will rise from now on," he told Reuters.
Al-Akhbar, a pro-Hezbollah newspaper, said political tensions had started to spill into the street.
"The 'battle' of Khaldeh ... gave a clear indication that the game in the street will quickly go out of control to burn the whole country," it said.