TRIPOLI, Lebanon (AFP) — Shops reopened their doors and traffic returned to the streets of Tripoli on Thursday as calm returned to the northern Lebanese city following a fresh bout of violence, witnesses said.

An AFP correspondent said armed men who had taken to the streets on Tuesday night were no longer to be seen, and clashes which saw about 30 buildings and 15 stores burnt and 57 buildings damaged by rocket and gunfire had died away.

The latest clashes, in which no casualties were reported, began less than 24 hours after rival factions had agreed to a truce following violence on Sunday and Monday which killed nine people.

The clashes have pitted Sunni supporters of the Western-backed majority in parliament against members of an Alawite sect loyal to the Hezbollah-led opposition, which is backed by Syria and Iran.

Combatants had traded heavy machine-gun fire, mortar rounds and rocket-propelled grenades during the fighting in the densely populated Tripoli neighbourhoods of Bab al-Tebbaneh, Jabal Mohsen and Al-Qobbe.

The AFP correspondent said that on Wednesday evening fighters from both factions dismantled barricades they had erected in the areas they controlled and the army was patrolling the streets of the three neighbourhoods in force.

Tripoli, Lebanon's second-largest city, has been periodically rocked by clashes between the Sunni militants and members of the Alawite community, a secretive offshoot of Shiite Islam.

But the latest fighting raised fears of a nationwide security breakdown amid stalled efforts by Prime Minister Fuad Siniora to form a national unity government in line with the Qatari-brokered deal in May.

The accord led to the election of army chief Michel Sleiman as president, ending a six-month vacuum in the top job, but rival politicians have continued to bicker over the distribution of key portfolios in the new government.