At least seven people have been killed and 30 others have been wounded in clashes in Lebanese city of Tripoli.
The deaths occurred after fighting broke out between supporters and opponents of the uprising against President Bashar al-Assad in Syria.
A woman and her son were killed by a rocket in the Bab al-Tebbaneh district, a mostly Sunni Muslim community which supports Syria's anti-regime opposition.
At least five people were wounded in Jabal Mohsen, an area mainly populated by pro-Damascus Alawites.
Sporadic gun and rocket fire broke out at midnight and continued through the night, forcing some residents of the port city to flee their homes.
The army and police have been deployed in Tripoli.
Sectarian violence has flared on a number of occasions in Tripoli since the revolt broke out in neighbouring Syria in March last year, including deadly street battles in May.
Bab al-Tebbaneh and Jabal Mohsen have been gripped by frequent fighting, reflecting a split between Lebanon's parties where the opposition backs the revolt in Syria, while a ruling coalition led by Hezbollah supports the Damascus regime.