The army has declared a night curfew in Lebanon's capital after at least two people were killed in clashes at a Beirut University. The fighting broke out between pro and anti-government activists.

The riot spread through the streets around Beirut Arab University, as students smashed parked cars in a battle that raged for hours.

Security officials weren't able to confirm the deaths but reported 17 people wounded. Some media outlets reported 25 people were hurt.

One group of students involved Sunni Muslims, loyal to the Lebanese government, while the others are Shiites who support the opposition Hezbollah.

One student was struck by a bullet in the head, but security forces don't know which group fired the fatal shot.

A government official told The Associated Press that the curfew would last from 8:30 p.m. Thursday until 6 a.m. Friday.

The melee at the university didn't just involve students. Vigilantes joined in, wearing construction hats and carrying makeshift weapons that included chair legs, pipes, garden tools, sticks and chains.

First police responded, and then the army called to fire tear gas and disperse the crowd.

"It is a religious duty. All must ... leave the streets and remain calm and restrain themselves and leave the arena for the army and the security forces to shoulder full responsibility to control the situation," Nasrallah said in an audio message.

The university melee came two days after a general strike called by the opposition turned into the worst day of violence since the political crisis began.

Fighting in Tripoli Tuesday left three people dead and 173 injured.

Gunmen from neighbouring districts -- one largely Sunni Muslim, the other largely Alawites, a Shiite Muslim offshoot -- fought each other as the Hezbollah-led opposition pushed to topple Prime Minister Fuad Saniora's Western-backed cabinet.

With files from The Associated Press