Seventeen people were reported killed in northern Lebanon Sunday - while fresh clashes were reported southeast of Beirut between the pro-Iranian Hezbollah and followers to Druze leader Walid Jumblatt, police said.
Machinegun fire and heavy artillery echoed throughout the village of Aitat, 20 kilometres southeast of Beirut, and sources close to Jumblatt told Deutsche Presse-Agentur dpa the army was trying to contain the situation.
A witness told dpa Jumblatt militiamen were seen carrying their guns and heading to the area. There were no immediate reports of casualties but people living in the area reached by telephone said mortar fire fell near their homes, and ambulance sirens wailed.
Seventeen people were earlier reported killed when heavy fighting broke out at dawn between pro- and anti-government supporters in northern Lebanon.
The situation eased off after army soldiers were sent into Lebanon's second largest city, where overnight there was heavy fighting in two areas, Bab al Tabbneh and Jabal Mohsen.
Sources in Tripoli told Deutsche Presse-Agentur dpa, that "massacres were registered in the fighting." Gunmen carrying machineguns and pistols were fighting street-to-street battles.
The fighting eased off by mid-morning when the army entered and called on all militias to pull back.
A security official said the fighting was between Sunni supporters of the Western-backed government and members of an Alawite sect loyal to Hezbollah, which is backed by both Syria and Iran.
He added that thousands of people were fleeing the clashes to safer areas after residents reported heavy machinegun fire and the thump of exploding rocket-propelled grenades.
Bab al-Tabbaneh is a Sunni district while Jabal Mohsen is mainly Alawite. The Alawites are an offshoot of Shiite Islam who revere Ali, the cousin and son-in-law of the Prophet Mohammed.
Syrian President Bashar al-Assad, whose government has been accused of backing Hezbollah, is an Alawite.
Beirut saw a relative calm return after four days of fierce sectarian fighting between mainly Sunni supporters of the ruling majority and Shiite opposition militias.
No armed elements could be seen on the streets early Sunday, but some barricades put up by militants remained and the airport road was shut for the fifth straight day.
The Shiite opposition announced on Saturday it was ending its takeover of large sectors of west Beirut after the army revoked government measures against Hezbollah, which had sparked days of deadly fighting.
"The opposition welcomes the army's decision and will proceed with the withdrawal of all its armed elements so that control of the capital is handed over to the military but it will continue its civil disobedience," an opposition statement said.
The announcement came shortly after the army said it was overturning a government decision to sack the head of Beirut airport security, who is close to Hezbollah, and to probe a Hezbollah communications network.
In a television address to the nation the western-backed premier Fouad Seniora accused Hezbollah, of staging an armed coup and urged the army to step in and restore order.
Seniora urged all Lebanese to stand for a minute of silence at noon (0900 GMT) on Sunday in remembrance of victims of the unrest and to express their rejection of the violence.
Most people in the capital were seen hanging Lebanese flags on their balconies and some even hanged placards that read "Lebanon is for all the Lebanese. Militias should get out of Beirut."
Near major hotels in Beirut, many foreigners who had been stuck in the capital, were seen taking buses leaving the country by road to Syria.
However, the eastern border crossing of Masnaa was still blocked by pro-government supporters.
"I left my house and came to the hotel on Thursday, and now I am heading back to my country through Syria," a Frenchwoman told dpa.
Lebanon's political crisis, which first erupted in November 2006 when six pro-Syrian ministers quit the cabinet, has left it without a president since November, when pro-Syrian Emile Lahoud stepped down.
The crisis in Lebanon is widely seen as an extension of the confrontation pitting the United States and its Arab allies against Syria and Iran.
The Arab League was set Sunday to hold an emergency meeting in Egypt on the crisis amid regional Sunni Muslim fears about Shiite Iran's influence in divided Lebanon.
Political analyst Rafik Khoury, did not expect much from the meeting.
"We cannot expect much from this meeting, but the Arab leaders should be aware that if the situation in Lebanon deteriorates it will spill outside the borders towards their countries and their regimes might be threatened as well," Khoury warned.