Residents of Tripoli said on Monday there had been "a massacre" in the Tajura and Fashlum districts of the Libyan capital, with indiscriminate shooting and air strikes and women among the dead.
"What happened today in Tajura was a massacre," one resident of the district said. "Armed men were firing indiscriminately. There are even women among the dead," adding that mosque loudspeakers were putting out appeals for help.
Another witness in Fashlum said that helicopters had landed what he called armed African mercenaries in the neighbourhood, and that the gunmen then opened fire on anyone in the street, causing a large number of deaths.
Both Fashlum and Tajura are suburbs of the Libyan capital.
In a dramatic international response, the airspace over the Libyan capital Tripoli has been closed until further notice, said a spokesman for the Austrian Army, which sought to evacuate European nationals from Libya on a military plane.
A coalition of Libyan Islamic leaders has issued a fatwa telling all Muslims it is their duty to rebel against the Libyan leadership and demanding the release of all jailed protesters.
The group also demanded the release of fellow Islamic scholar Sadiq al-Ghriani, who was arrested after criticizing the government, and "all imprisoned demonstrators, including many of our young students".
Calling itself the Network of Free Ulema of Libya, the group of over 50 Muslim scholars said the government and its supporters "have demonstrated total arrogant impunity and continued, and even intensified, their bloody crimes against humanity.
"They have thereby demonstrated total infidelity to the guidance of God and his beloved Prophet (peace be upon him)," said the undated statement obtained by Reuters on Monday.
"This renders them undeserving of any obedience or support, and makes rebelling against them by all means possible a divinely ordained duty," said the scholars, who asked not to be named for security reasons.
Open dissent by established Muslim clerics is rare in North Africa, but the crackdown on protesters rallied the scholars to form the previously unknown Network of Free Ulema.
They have thereby demonstrated total infidelity to the guidance of God and his beloved Prophet
Free Ulema of Libya
Their first statement issued on Saturday denounced the government for firing on demonstrators who were demanding "their divinely endowed and internationally recognized human rights" and stressed the killing of innocent people was "forbidden by our Creator."
Libya's justice minister Mustapha Abdeljalil resigned in objection to "the excessive use of force" against demonstrators in the north African country, a Libyan newspaper reported on Monday.
"Minister Mustapha Abdeljalil said, in a telephone call to Quryna newspaper, he had resigned in protest at the violence and excessive use of force by security forces against unarmed demonstrators," Quryna reported on its website.
The country’s ambassadors to the UK, Indian and Indonesia have also resigned to protest against the crackdown on protesters and the staff of Libyan U.N. mission has said they would now represent only the people of Libya.
Fighter jets in Malta
Separately, the pilots of two Libyan fighter jets who landed in Malta on Monday said they had defected after they were ordered to attack protesters in Benghazi, Maltese military and official sources told AFP.
The two men told Maltese military officers on the ground that they were senior colonels in the Libyan air force and one of them requested asylum, as they were getting out of their single-seater Mirage F1 jets.
"One of the pilots requested political asylum," a government spokesman said.
They said they had been forced to flee their air base in Benghazi after it was taken over by protesters, the sources said.
"The two pilots are being held by police for further investigations," the Maltese government said in a statement.
The four-decade-old rule of Libyan leader Muammar Gaddafi has been shaken by days of violent protests which reached the capital Tripoli for the first time on Monday.
Ibrahim Dabbashi, the Libyan deputy permanent representative to the United Nations, told Al Arabiya that the Libyan people are ready to offer more sacrifices and to continue until the end, until the fall of the tyrant.
The government of President Hugo Chavez denied on Monday reports that Gaddafi was traveling to Venezuela following violent protests in the fellow OPEC member nation.
Dabbashi said if Gaddafi decides to escape he expects him to go to Chad or Niger but not to Venezuela.
Attracted to Gaddafi's revolutionary past, the socialist Chavez also casts himself as an anti-U.S. stalwart on the international stage, and the pair enjoy warm ties.
Adding to media rumors, British Foreign Secretary William Hague said earlier on Monday he had seen information to suggest Gaddafi had fled Libya and was on his way to the South American oil-exporting nation..
The Venezuelan government "denies such information," a senior government source told Reuters.
He added it was unlikely the leader who has ruled Libya for more than 40 years would come to Venezuela.
"It is not planned," the source said.
Gaddafi's rule appeared in increasing jeopardy on Monday as anti-government protests reached the capital for the first time, leaving dozens dead at the hands of the security forces.
Diplomats said the information Hague referred to was separate from reports in recent days by several Arab world media that Gaddafi was headed to Venezuela.
Chavez, a popular figure in much of the Muslim world who took office 12 years ago, has visited Libya half a dozen times. Gaddafi traveled to Venezuela in 2009 and gave Chavez one of the large tents he holds court in on foreign visits.
Libya is Africa's fourth biggest oil exporter, while Venezuela is South America's top oil exporter.
U.S. crude oil futures surged by more than $5 a barrel to over $91 on Monday, their biggest one-day gain in over two years, in part on the violence in OPEC producer Libya, while European Brent crude surged by more than $2.70 a barrel to hit a post-2008 high of $105.28 a barrel.
Venezuelan officials seemed surprised by the rumor Gaddafi may come, though Chavez is famous for taking unexpected decisions.