Lebanese violence reaches Tripoli
Machine-guns and rocket-propelled grenades are being used and people have been fleeing their homes, correspondents say.
Three people died in the northern city on Saturday.
Meanwhile, an uneasy calm has descended on the capital, Beirut, scene of four days of bloody street battles.
More than 30 people died in those clashes between Hezbollah fighters and government supporters.
On Saturday, Hezbollah agreed to pull its fighters off the streets of the Muslim western part of the city after the army overturned government measures aimed at curbing the group.
Sunni supporters of the Western-backed government have been fighting members of an Alawite sect loyal to Hezbollah in Tripoli, an unnamed security official told AFP news agency.
About 7,000 people have fled from the city's Bab al-Tebbaneh district, which marks the front line, the official said.
Earlier, pro-government demonstrators burnt offices of the pro-Syrian Baath Party offices.
They stamped on posters of Syrian President Bashar al-Assad and Hezbollah leader Hassan Nasrallah.
They could also be seen throwing furniture and files from the Baath offices and a local opposition politician's office, The Associated Press reports.