Libyan security forces fired on crowds of protesters in Tripoli as Muammar Gaddafi struggled desperately to hold on to power in what has become the bloodiest crackdown yet on pro-democracy protesters in the Arab world.
With diplomats resigning en masse and two senior fighter pilots defecting to Malta after refusing to attack demonstrators, the Libyan leader looked beleaguered at home and unwelcome anywhere abroad.
"What's going on in Libya is a real genocide," said the country's deputy UN ambassador, Ibrahim al-Dabashi.
One Tripoli resident told al-Jazeera TV: "Death is everywhere," as he described air attacks on the terrified city. "Why is the world silent?"
Gaddafi appeared briefly on Libyan state TV to deny reports that he had fled the country. "I want to show that I'm in Tripoli and not in Venezuela. Do not believe the channels belonging to stray dogs," he said, reported by the station as speaking outside his house. He was holding an umbrella in the rain and leaning out of a vehicle.
"I wanted to say something to the youths at the Green Square [in Tripoli] and stay up late with them but it started raining. Thank God, it's a good thing," Gaddafi said in a 22-second appearance.
Libyan state TV earlier said military operations were under way against "terrorist nests" and there were predictions of a bloodbath by a desperate regime which feels the end approaching.
Developments on Monday included:
• The US ordering all non-emergency staff to leave Libya – a sure sign that the crisis is worsening.
• Libya's justice minister announcing he was quitting, as did ambassadors in at least seven countries.
• Benghazi, Libya's second city and the scene of alleged massacres in recent days, was reported to be in the hands of anti-government protesters, but violence continued unabated. Residents were organising vigilante groups to protect themselves and distribute food.
• Information remained fragmentary and confused, with phone lines and the internet intermittently cut and al-Jazeera satellite TV reportedly jammed by Libyan intelligence.
• Qatar condemned the use of military aircraft and machine guns against unarmed protesters and called for an emergency meeting of the Arab League.
• The death toll passed 250 after six days of unrest but this is a conservative estimate. Al-Jazeera quoted medical sources in Tripoli saying 61 people had died in the latest protests there. The International Federation of Human Rights estimated the death toll at 300 to 400.
• Libyan army officers issued a statement urging fellow soldiers to "join the people" and help remove Gaddafi. Tribal and religious leaders also spoke out against Gaddafi, with a coalition of Islamic scholars issuing a fatwa telling Muslims it was their duty to rebel against the regime.
• Reports from Tripoli said the building used by the general people's congress was on fire. Protests spread to the capital on Sunday after previously being confined largely to the east of Libya.
• Unconfirmed reports described firing from presumed Libyan naval vessels in the Mediterranean off Tripoli. The mood in the capital and its residential suburbs was tense and chaotic, with local people barricading themselves into neighbourhoods or staying inside, afraid of foreign mercenaries paid to shoot to kill.
Libyans had reacted furiously to Sunday night's speech by Gaddafi's son Saif al-Islam, who warned of civil war and vowed to fight to the "last bullet" and claimed the country could be taken over by Islamists and divided by "imperialists". TV clips showed furious people throwing shoes at the TV screen as he spoke.
"The regime is clutching at straws," a Tripoli man told a friend abroad. "Their only hope is to create fear in the hearts of Libyans by planting the seed of fitna (sectarian strife). Fitna is often used by the weak to create upheaval and chaos in order to achieve division. We are united and we will continue."
Most analysts believe that after the extraordinary events of the last few days, the end of Gaddafi's rule is approaching.
"There is nowhere for him to go in the Arab world – the Saudis hate him," said Charles Gurdon of Menas Associates, a London-based Middle East consultancy. "It would have to be somewhere like Zimbabwe or Venezuela. It may take 24 hours or a couple of months – no one really knows. But the end is nigh."
UN secretary general Ban Ki-moon, who spoke at length to Gaddafi, condemned the escalating violence in Libya and told him it "must stop immediately".
US secretary of state Hillary Clinton strongly condemned the violence in Libya and called on the Libyan government to respect the rights of its people. "We join the international community in strongly condemning the violence in Libya," she said in a statement. "Now is the time to stop this unacceptable bloodshed." The Libyan government has a responsibility to respect the universal rights of its people, including the right to free expression and assembly, Clinton said.
David Cameron, visiting neighbouring Egypt, called the crackdown "appalling."
"The regime is using the most vicious forms of repression against people who want to see that country which is one of the most closed and one of the most autocratic make progress," he said.
Analysts were looking ahead to the post-Gaddafi era, but admitted that after 41 years of his rule the country is a "black box" about which it is hard to make predictions. "Everything is fragmented, there are no obvious leaders," said George Joffe of Cambridge University. "Politicians have been functionaries of the regime. The only people with power were in the Gaddafi family or in the tribes."