Lebanon's caretaker prime minister has ordered the military to take control of Tripoli for six months to quell spiralling sectarian violence.
The decision was taken during a high-level security meeting called after sectarian clashes resulted in the deaths of at least 12 people.
"We decided to commission the army to take all necessary measures to maintain security in Tripoli for six months and place the military forces as well as police under its command," the prime minister Najib Mikati said.
The civil war in neighbouring Syria has polarised relations between Sunni and Shia across the Middle East and violence has spilled over into Lebanon, a country that was itself torn apart by a bloody civil war from 1975-90.
Syria's Bashar al-Assad and his ruling elite belong to the Alawite Muslims, a Shia offshoot, while rebels are predominantly Sunni.
Tripoli, Lebanon's second largest city, is mainly Sunni Muslim but is also home to a small Alawite community.
Syrian government flags are flown from houses in Tripoli's hill district of Jabal Mohsen, where most Alawites live, while Syrian rebel banners can be seen in the largely Sunni neighbourhood of Bab Tabbaneh.
Gun battles erupted at the end of last week across the two impoverished neighbourhoods after Sunni gunmen shot the brother of a commander of an Alawite militia. More than 100 people were wounded.