Clashes have erupted outside the Libyan parliament in the capital, Tripoli, in an attack being claimed by forces loyal to a retired army general accused of launching a coup attempt.
Al Jazeera's Omar al-Saleh, reporting from Tripoli, said the city had "turned into somewhat a battlefield".
Saleh quoted eyewitnesses as saying a large convoy of vehicles with heavy machine guns stormed the General National Congress.
"There were few cars set on fire. There was heavy fighting. The situation is very tense."
Saleh said a spokesman of retired Libyan Major General Khalifa Haftar said the attackers were affiliated with Haftar's forces.
However, according to the Libyan News Agency, the attacking force belongs to the Zintan brigade, a rebel group from 170km south-west of Tripoli, which controls the city's international airport.
Zintar forces have not yet said the attack was undertaken for Haftar.
Benghazi clashes
The retired general has been carrying out a military campaign in Benghazi - using government aircraft and troops without authorization - against militias since Friday.
At least 70 people have died and another 140 have been injured in the campaign.
Haftar vowed to press on with his operation after Libya's interim Prime Minister Abdullah al-Thinni on Saturday denounced his forces as "outlaws" and called on all parties to observe restraint.
On Sunday he was preparing to renew his offensive in the eastern city after being accused by the authorities of an attempted coup.
In a press conference on Sunday, he denied his actions amounted to a coup attempt.
Libya has been struggling with chaos as its government, parliament and nascent armed forces are unable to impose their authority over brigades of former opposition forces and militias who helped oust Muammar Gaddafi in 2011 but now defy the state.
PHOTO CAPTION
General Khalifa Haftar speaks during a news conference at a sports club in Abyar, a small town to the east of Benghazi. May 17, 2014
Al-Jazeera