Protesters have clashed with police and government supporters in the eastern Libyan city of Benghazi, reports say.
Demonstrators gathered in the early hours of Wednesday morning in front of police headquarters and chanted slogans against the "corrupt rulers of the country", Al Jazeera's sources said.
Police fired tear gas and violently dispersed protesters, the sources said without providing further details.
The online edition of Libya's privately-owned Quryna newspaper, which is based in Benghazi, said the protesters were armed with petrol bombs and threw stones.
According to the newspaper, 14 people were injured in the clashes, including three demonstrators and 10 security officials.
In a telephone interview with Al Jazeera, Idris Al-Mesmari, a Libyan novelist and writer, said that security officials in civilian clothes came and dispersed protesters by using tear gas, batons and hot water.
Al-Mesmari was arrested hours after the interview, unconfirmed reports say.
'Day of rage' called
Anti-government protesters have also called on citizens to observe Thursday as a "Day of Rage". They are hoping to emulate recent popular uprisings in Egypt and Tunisia to end Colonel Muammar Gaddafi's 41-year-old rule.
The rare protests reportedly began after relatives of those killed in a prison massacre about 15 years ago took to streets. They were joined by scores of other supporters.
The relatives were said to have been angered by the detention of Fathi Terbil, human rights lawyer and official spokesman of the victims' families, who was arrested by the Libyan security forces, for no apparent reason.
However, Terbil was later released, according to reports.
Twelve-hundred prisoners were killed in the Abu Slim prison massacre on June 29, 1996, after they had objected to their inhumane conditions inside the prison.
Those killed were buried in the prison's courtyard and in mass graves in Tripoli. The families of the victims have been demanding that the culprits be punished.
Mohammed Maree, an Egyptian blogger, said "Gaddafi's regime has not listened to such pleas and continues to treat the Libyan people with lead and fire."
"This is why we announce our solidarity with the Libyan people and the families of the martyrs until the criminals are punished, starting with Muammer and his family."
Libyan state television reported that rallies were taking place all over the country early this morning “in support of the rule of the people by the people”.
A group of prominent Libyans and members of human rights organisations have also demanded the resignation of Gaddafi.
They said that the Libyans have the right to express themselves through peaceful demonstrations without any threat of harassment from the regime.
The demands came in a statement signed by 213 personalities from different segments of the Libyan society, including political activists, lawyers, students, and government officials.
Meanwhile, a local human rights activist told Reuters news agency that the authorities have decided to release 110 prisoners jailed for membership of banned organisation, the Libyan Islamic Fighting Group.
The prisoners to be freed on Wednesday, are the last members of the group still being held and will be set free from Tripoli's Abu Salim jail, Mohamed Ternish, chairman of the Libya Human Rights Association said.
Hundreds of alleged members of the group have been freed from jail after it renounced violence last year.