Four people were killed and 15 wounded in overnight gun battles in the Lebanese city of Tripoli in a second night of fighting between Sunni and Alawite gunmen loyal to different sides in the conflict in neighbouring Syria, a military source said yesterday.

In the capital Beirut on Monday, tensions eased after troops fanned out across the city to clear the streets of gunmen who had clashed on Sunday night.

The violence flared after the assassination of senior Lebanese security official Wissam al Hassan, who was opposed to the Syrian leadership, in central Beirut on Friday.

The bombing and the ensuing clashes brought the civil war in Syria into the heart of Lebanon and triggered a political crisis, with the opposition demanding the resignation of the mostly pro-Damascus cabinet of Prime Minister Najib Mikati.

The fighting in Tripoli took place between the neighbouring areas of Bab al Tabbaneh, a Sunni Muslim stronghold, and Jebel Mohsen, an Alawite district.

Three Sunnis and one Alawite were killed and 15 people were wounded, a military source said. Residents said combatants traded machine gun-fire and rocket-propelled grenades.

Yesterday morning, Tripoli's centre was busy and traffic moved freely. Lebanese soldiers kept watch in armoured vehicles mounted with heavy machine guns. But shops close to the combat zone were shuttered.

A fruit market on the front line was closed and residents said they feared snipers. Teenagers in T-shirts with guns hid behind buildings to peek out up the hill into Jebel Mohsen.

Tripoli's Sunni Muslims support the Syrian rebels fighting to overthrow President Bashar al Assad, who are mostly from Syria's Sunni majority.

Mr Assad is a member of the Alawite sect, an offshoot of Shi'ite Islam.

He can count on the support of Hezbollah, a powerful Shi'ite Islamist armed group that is part of the Mikati government.

The violence in Tripoli on Monday night brought the toll to at least 10 dead and 65 wounded since Friday.