TRIPOLI (Reuters) - Hundreds of people clashed with police and government supporters overnight in the eastern Libyan city of Benghazi, a witness and local media said, in a rare show of unrest in the oil exporting country.
Protesters angered by the arrest of a human rights activist threw petrol bombs, set cars ablaze and chanted "no God but God!" in clashes that left dozens injured, according to reports from the city.
Libya has been tightly controlled by leader Muammar Gaddafi for over 40 years but has also felt the ripples from popular revolts in its neighbours Egypt and Tunisia.
Libyan state television said that rallies were held in the early hours of Wednesday morning across the country in support of Gaddafi, who is Africa's longest serving leader.
Reports from Benghazi, about 1,000 km (600 miles) east of the Libyan capital, indicated the city was now calm but that overnight, protesters armed with stones and petrol bombs had set fire to vehicles and fought with police.
The protesters were angry about the arrest of a human rights campaigner and demanded his release.
Gaddafi opponents used the Facebook social networking site to call on people to go out onto the streets across Libya on Thursday for what they described as a "day of rage".
Quryna newspaper, which is based in Benghazi, quoted Abdelkrim Gubaili, the director of a local hospital, as saying 38 people were hurt in the clashes, most of them members of the security forces. He said they had all been discharged.
"Last night was a bad night," a Benghazi resident, who did not want to be identified, told Reuters by telephone.
"There were about 500 or 600 people involved. They went to the revolutionary committee (local government headquarters) in Sabri district, and they tried to go to the central revolutionary committee ... They threw stones," he said.
"Now Benghazi is quiet. The banks are open and the students are going to school," the same witness said later.
Some Libyans complain about high unemployment, income inequality and limits on political freedoms, but analysts say an Egypt-style revolt is unlikely.
A video clip posted on the YouTube site by someone who said it was recorded in Benghazi on Tuesday night showed a crowd of people outside what looked like a government building chanting: "No God but God!" and "Corruption is the enemy of God."
Quryna newspaper said people demanding the release of the rights activist, Fethi Tarbel, were armed with petrol bombs and threw stones at police in Benghazi's Shajara square.
People in Benghazi and the region around it have a history of distrust of Gaddafi's rule. Of the hundreds of people jailed in Libya over the past decade for membership of banned Islamist militant groups, many are from the city.
One analyst said it was unlikely unrest would spread nationwide, but that the violence in Benghazi could add to the numbers taking part in the protest planned for Thursday.
"Our argument has always been that Libya is very different from Tunisia and Egypt because they have got the money to buy off people," said Charles Gurdon, a Libya expert at consultancy Menas Associates.
"Having said that, after Tunisia people said that Egypt would not be the same," he said. "A lot will depend on how heavy-handed the security forces are."
Libyan state television showed footage of an early-morning rally in the Libyan capital of government supporters, while the state-run Jana news agency reported pro-Gaddafi rallies in other cities, including Benghazi.
The agency reported that participants held up portraits of Gaddafi and chanted: "We sacrifice our blood and souls for you, our leader!" and "We are a generation built by Muammar and anyone who opposes it will be destroyed!"
At the Abu Salim prison near Tripoli, 110 men jailed for membership of the banned Libyan Islamic Fighting Group (LIFG) were set free, though local rights activists overseeing the release said it had nothing to do with events in Benghazi.
"I am pleased to be out after 13 years in prison," Mustafa Salem, from Benghazi, told Reuters as he prepared to walk out of the prison gate. "I hope I will be able to ... rebuild my life."
The prison, which has been used to hold government opponents and Islamist militants, was the scene of violent clashes in June 1996 in which 1,000 inmates were shot dead.
Dozens of men accused of membership of the LIFG have been freed since last year, when its leaders renounced violence.