Dozens of people were injured in clashes in Benghazi, a hospital in the eastern city said Wednesday, as Libya braced for a "Day of Anger" following revolts in neighboring Egypt and Tunisia.
The director of al-Jala hospital, Abdelkarim Gubeaili, told AFP that 38 people were treated for light injuries.
Hundreds of Libyan protesters have taken to the streets of the country's second largest city to demand the government's ouster in the first sign that the region's unrest has spread to the North African Arab nation.
A local human rights activist, meanwhile, told Reuters that Libya will release 110 prisoners jailed for membership of banned militant organisation the Libyan Islamic Fighting Group.
The prisoners are the last members of the group still being held and will be set free from Tripoli's Abu Salim jail, chairman of the Libya Human Rights Association Mohamed Ternish told Reuters.
Hundreds of alleged members of the group have been freed from jail after it renounced violence last year.
Witnesses say protesters in the port city of Benghazi chanted slogans Wednesday demanding the resignation of Prime Minister Baghdadi al-Mahmoudi. There were no calls, however, for longtime leader Moammar Gaddafi to step down.
As in the Egyptian and Tunisian uprisings, Libyans are using social networking websites like Facebook to call for a day of protests on Thursday.
Libyan state television said separately that rallies were being held across the oil exporting country on Wednesday in support of Libyan leader Muammar Gaddafi.
The online edition of Libya's privately-owned Quryna newspaper, which is based in Benghazi, said the crowd were armed with petrol bombs and threw stones.
It said they protested outside a local government office to demand the release of a human rights activist, and then went to the city's Shajara square where they clashed with police and government supporters.
It said the rioting was now over and that government supporters had taken over the square. Fourteen people were injured including 10 police officers, but none of the injuries were serious, the newspaper said.
A Benghazi resident contacted by Reuters said the people involved in the clashes were relatives of inmates in Tripoli's Abu Salim jail, where militants and government opponents have traditionally been held.
"Last night was a bad night," said the witness, who did not want to be identified.
"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.
"It is calm now."
Libyan state television showed footage of a rally in the Libyan capital, Tripoli, of government supporters.
Quryna newspaper said security forces and demonstrators clashed late on Tuesday in what it branded the work of "saboteurs" among a small group of protesters.
The security forces intervened to halt a confrontation between supporters of Libyan leader Moamer Kadhafi, who has been in power for more than 40 years, and the demonstrators, said the paper close to Kadhafi's son, Seif al-Islam.
The veteran leader is facing rare Internet calls for protests on Thursday by activists buoyed by the ouster of veteran strongmen on Libya's borders, in Egypt and Tunisia.
One of the Facebook groups calling for a "Day of Anger" in Libya and anti-regime protest that had 4,400 members on Monday more than doubled in number to 9,600 by Wednesday morning after the Benghazi unrest.
The European Union, meanwhile, urged Libyan authorities to allow "free expression" in the North African nation and listen to protesters.
The protest started as a sit-in by families of prisoners killed in a 1996 shooting in Tripoli's Abu Salim prison demanding the release of their lawyer, Fethi Tarbel, Libyan newspapers said.
Tarbel had been detained for having "spread rumours that the prison (in Tripoli) was on fire," according to Quryna, but was released after the demonstration.
But the crowd of protesters grew and they began chanting anti-regime slogans such as "The people will end the corruption" and "The blood of the martyrs will not be in vain," before police moved in to disperse them.
Police used force to disperse the crowd gathered outside a police post, it said, while the BBC quoted witnesses as saying stones were thrown at police who responded with tear gas, water cannon and rubber bullets.
Marchers later hurled Molotov cocktails in a downtown square, damaging cars, blocking the road and hurling rocks, Quryna said.
Soon afterwards, state television showed hundreds of demonstrators in the streets of Benghazi as well as Tripoli, Syrte and Sebha in support for Kadhafi, who seized power in a 1969 coup which ousted a Western-backed monarchy.
Quryna said the unrest coincided with calls from exiled Libyan opposition figures living in the United States and Britain for "a campaign of incitement" against Tripoli broadcast on the American Arabic-language satellite Al-Hurra.
A website, Libya al-Youm, also said the unrest prompted a show of strength by supporters of Kadhafi in Benghazi and a number of other cities.
State television ran footage of pro-regime demonstrators on foot and in cars, waving Libyan flags and portraits of Kadhafi. They chanted slogans against Arab news channel Al-Jazeera, accused by the regime of inciting unrest.
Thursday's protest has been called to commemorate the deaths of 14 protesters in 2006 in an Islamist rally in Benghazi.
The European Union on Wednesday urged the Libyan authorities to allow "free expression" in the North African nation and listen to protestors following clashes in the city of Benghazi.
Like protest movements elsewhere in the Middle East, dissidents have been using the Internet in a bid to rally support in a country where the media are tightly controlled by the state.
Under the banner "The February 17 Intifada (Uprising): A Day of Strikes in Libya," one Facebook group has called for a popular uprising.
Another group of nearly 8,000 members called for Libyans to take to the streets for a "Day of Anger against corruption and nepotism."
In a petition received by AFP on Monday, more than 200 exiled Libyan opposition figures called for Kadhafi's ouster and the right to hold peaceful demonstrations in the country.
A total of 69 people were also wounded in the 2006 protest in which the consulate of former colonial power Italy was targeted by demonstrators angry at cartoons of the Prophet Mohammed.