TRIPOLI (Reuters) - Members of a Libyan army unit told Benghazi residents on Sunday they had defected and "liberated" Libya's second city from troops supporting veteran leader Muammar Gaddafi, two residents said.
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," al-Mana said by telephone. It was not possible to independently verify the report.
Obaidi said the bodies of 50 people killed on Sunday had arrived at the hospital in the late afternoon. Most had died from bullet wounds.
Sunday's bloodshed follows the deaths of scores of protesters on Saturday in one of the most violent days since protests began sweeping through the Arab world two months ago.
Residents said tens, perhaps hundreds of thousands of protesters had taken to the streets of the city to bury scores of dead killed in the last 24 hours. A witness said security forces opened fire on them.
The United States said it was "gravely concerned" by what it called credible reports hundreds of people had been injured or killed.
"Libyan officials have stated their commitment to protecting and safeguarding the right of peaceful protest. We call upon the Libyan government to uphold that commitment and hold accountable any security officer who does not act in accordance with that commitment," said State Department spokesman Philip Crowley.
Protesters, inspired by uprisings in neighbouring Tunisia and Egypt, are demanding an end to the 41-year rule of strongman Gaddafi. His security forces have responded with a violent crackdown. Communications are tightly controlled, and Benghazi is not accessible to international journalists.
Human Rights Watch said 84 people were killed in the city on Saturday, bringing the death toll in four days of clashes mainly in the east of the country to 173 before Sunday's violence.
"A massacre took place here last night," one resident, who did not want to be named, told Reuters by telephone on Sunday.
A leading tribal figure who requested anonymity said security forces, mainly confined to a compound, had been venturing out of their barracks and shooting protesters in the street in "cat and mouse chases."
Clashes were taking place on a road leading to a cemetery where thousands had gone to bury the dead.
"The situation is very tense and scattered fires have erupted in revolutionary committee headquarters and other buildings," he said.
"DOZENS OF MARTYRS"
Piecemeal accounts suggested the streets of Benghazi, about 1000 km (600 miles) east of the capital Tripoli, were largely controlled by anti-government protesters, under periodic attack from security forces who fired from their high-walled compound.
A resident said some 100,000 protesters had headed on Sunday for the cemetery "to bury dozens of martyrs" killed on Saturday.
Another witness told Reuters thousands of people had performed ritual prayers in front of 60 bodies laid out in the city. Women and children were among a crowd of hundreds of thousands that had come out onto the Mediterranean seafront and the area surrounding the port, he said.
"The protesters are here until the regime falls," he said.
The Libyan government has not released any casualty figures. A text message sent to mobile phone subscribers on Sunday said protesters in the east were trying to break the region away from central rule.
"The deaths in Benghazi and Al Bayda (a nearby town), on both sides, were the result of attacks on weapons stores to use in terrorising people and killing innocents," it said. "All Libyan sons, we have to all stand up to stop the cycle of separation and sedition and destruction of our beloved Libya."
A senior Libyan security source said a group believed to be criminals had launched an attack on the Benghazi municipal building, blew it up, seized rifles and fired randomly in order to create an opportunity to escape.
The government has disrupted the Internet, used by protesters to organise.
Al Jazeera, the Arabic television station whose coverage has played a big role in protests throughout the Middle East and North Africa, said its satellite transmissions across the region had been jammed. The Lebanese telecoms minister said the jamming appeared to come from Libya.
"STOP THE MASSACRE NOW"
The crackdown prompted about 50 Libyan Muslim religious leaders to issue an appeal, sent to Reuters, for the security forces, as Muslims, to stop the killing.
"We appeal to every Muslim, within the regime or assisting it in any way, to recognise that the killing of innocent human beings is forbidden by our Creator and by His beloved Prophet of Compassion (peace be upon him) ... Do NOT kill your brothers and sisters. STOP the massacre NOW!" the appeal said.
Libya is a major energy producer with significant investment from Britain's BP Plc, Exxon of the United States and Italy's ENI among others.
British Foreign Secretary William Hague urged Libya to begin dialogue with anti-government protesters and implement reforms, in a phone call to a son of Gaddafi on Sunday.
In Brussels, the Hungarian EU presidency said Libya had told the European Union it would stop cooperation with the bloc in stemming illegal migration to Europe if the EU encourages pro-democracy protests in the country.
Gaddafi's fate may hinge on whether the unrest remains confined largely to the eastern Cyrenaica region around Benghazi, where his support has traditionally been weaker than in other parts of the country.
(Additional reporting by Hamid Ould Ahmed in Algiers, Suleiman al-Khalidi in Amman, Tom Heneghan in Paris; Writing by Christian Lowe and Marie-Louise Gumuchian; Editing by Diana Abdallah and Peter Graff)
