Violent clashes continued into the night in Libya on Sunday between anti-government protesters and supporters of longtime leader Moammer Gadhafi. Some 200 people have been reported dead since the demonstrations erupted six days ago.

The violence spilled into central Tripoli late Sunday, after Libyans protesting against Gadhafi's four-decade rule had appeared to control the streets of Benghazi, the country's second largest city. At least 50 people were killed on Sunday alone, doctors said, in the bloodiest of multiple revolts now rocking the Arab world.

Open gallery view Pro-Gadhafi supporters gather in Green Square after traditional Friday prayers in Tripoli, Libya, Friday, Feb. 18, 2011. Credit: AP

Witnesses said Benghazi was in chaos, with government buildings ransacked and troops and police forced to retreat to a fortified compound, from where they picked off demonstrators with sniper and heavy-weapons fire.

"The security forces are in their barracks and the city is in a state of civil mutiny," one witness told Reuters.

The head of the Al-Zuwayya tribe in eastern Libya threatened on Sunday to cut off oil exports unless authorities stop what he called the "oppression of protesters", Al Jazeera quoted him as saying on Sunday.

Resident witnesses said that members of a Libyan army unit told Benghazi residents on Sunday night that they had defected and "liberated" the city from forces supporting veteran leader Gadhafi.

Habib al-Obaidi, who heads the intensive care unit at the main Al-Jalae hospital, and lawyer Mohamed Al-Mana, told Reuters members of the "Thunderbolt" squad had arrived at the hospital with soldiers wounded in clashes with Gaddafi's personal guard.

"They are now saying that they have overpowered the Praetorian Guard and that they have joined the people's revolt," Mohamed said by telephone. It was not possible to independently verify the report.

Meanwhile, Libya's representative to the Arab League has tendered his resignation in protest to "oppression against protesters", Al Jazeera's Mubasher (live) channel reported on Sunday.

Tens of thousands gathered in Benghazi on Sunday for funerals of protesters killed by Libyan security forces. Libyan forces fired machine-guns at mourners marching in a funeral procession for anti-government protesters, resuming the violent pattern of the previous days.

Benghazi has been at the center of the six-day revolt, which began series of protests inspired by popular revolts in neighboring Egypt and Tunisia, but was met by a fierce response.

Libyan analysts say it is unlikely for the moment that Gadhafi will be overthrown because the unrest is largely confined to the eastern Cyrenaica region, where his support has traditionally been weaker than in the rest of the country.

The Libyan government has not released any casualty figures.