Two people were reported killed and more than 16 people injured when violence broke out between Sunni Muslims who oppose Syrian President Bashar Assad and Alawites who support him.
The fighting in the city, which is about 25 kilometres from the Syrian border, began Monday. The Lebanese army intervened Monday evening to break up the fighting but it started up again on Tuesday morning.
- Syria crisis spreads to neighbouring Lebanon
The two sides are reported to have exchanged machine gun fire and rocket propelled grenades.
A spate of sectarian kidnappings in Lebanon in the past week has left many Syrians living in the country in fear, CBC's Derek Stoffel reported.
Last week, more then 20 people, some described as a members of the Syrian rebel forces, were kidnapped in Lebanon by members of a powerful Shia clan.
"The situation in Beirut has become more dangerous than we ever imagined," said Khalil Hassan, a long-time Syrian anti-government activist.
Beirut has been home to all kinds of people opposed to the Syrian regime for years now, but Hassan said that's changing.
Untill Hassan finds a country to offer him shelter, he says he's forced to remain in Lebanon and endure the threats that now confront him.