Rebels advanced on the Libyan capital Sunday as US President Barack Obama urged Muammar Gaddafi to step down "now" amid growing fears that his teetering four-decade rule could descend into civil war.
The UN Security Council imposed a travel and assets ban on Gaddafi's regime and ordered an investigation into possible crimes against humanity by the Libyan strongman, the first time any such decision has been made unanimously.
Fears of a full-scale civil war as Gaddafi loses his grip on power have prompted countries to evacuate tens of thousands of citizens and close down embassies, to escape reported gunfire, looting and food shortages.
Rebels are closing in on the capital, where Gaddafi loyalists have been carrying out orders to shoot on sight, witnesses said.
A resident told AFP that tanks and all-terrain vehicles driven by regime partisans were patrolling almost deserted streets.
"This escape of mine makes me feel I am in heaven," said Mohammed Sali, 63, an engineer in the first batch of Indian evacuees to return home.
"One man came and put the knife on my neck. He took all my belongings - laptop, chain, even my car.
"We heard gunshots every day... People have to go without food and water for three or four days as the situation there is bad. People are on the streets... police stations have been burnt down. There is no safety, no police."
Russia became the latest country to put pressure on the Libyan regime with Foreign Minister Sergei Lavrov telling Libyan counterpart Musa Kusa that Moscow condemned the unacceptable use of force against civilians.
Libya's former justice minister announced he was forming a transitional government to replace Gaddafi's crumbling regime, which now controls only some western areas around the capital and a few longtime bastions in the arid south, reporters and witnesses say.
Mustafa Abdel Jalil said the new administration would include commanders of the regular army, much of which has defected to the opposition, and would pave the way for free and fair elections in three months' time.
"Our national government has military and civilian personalities. It will lead for no more than three months, and then there will be fair elections and the people will choose their leader," Abdel Jalil told reporters in the eastern town of Al-Baida, an opposition stronghold.
It was not immediately clear whether other cities that liberated themselves had coordinated the move with Abdel Jalil, who resigned on Monday in protest at the increasingly deadly crackdown on opposition to the regime.
Gaddafi's son, Seif al-Islam, once regarded as a reformist possible heir, said the crisis had "opened the doors to a civil war."
Amid growing shortages in the import-dependent, oil-producing North African nation, people joined long queues for bread and petrol on Saturday.
In Washington, Obama said Gaddafi needs to "leave now," having lost the legitimacy to rule.
It was the US president's most direct demand yet that Gaddafi step down and was coordinated in a telephone call with German Chancellor Angela Merkel, the White House said.
The UN Security Council voted to order an investigation into possible crimes against humanity by the Libyan regime, and impose an arms embargo, and travel bans and asset freezes targeting Gaddafi and his family and inner circle.
The resolution cited "gross and systematic violation of human rights, including the repression of peaceful demonstrators" and incitement to hostility and violence "from the highest levels of the Libyan government."
The United Nations says that more than 1,000 people have been killed in the crackdown by Gaddafi loyalists.
The Security Council said it was referring the bloodshed to the International Criminal Court because "the widespread and systematic attacks" in Libya against civilians "may amount to crimes against humanity".
In Libya's third city Misrata, which fell to the opposition in deadly clashes over the past few days, helicopter-borne regime mercenaries fired on a funeral procession, a witness told AFP.
Heavy weapons fire was heard in the background as the witness said by telephone that the hired men shot at mourners who were about to enter a mosque.
The mercenaries also fired on a building housing an opposition radio station. It was unclear if there were casualties.
Britain, Canada and the United States have pulled diplomatic staff out of Tripoli and closed their embassies.
After criticism about delayed rescue efforts, two British C130 Hercules swooped into the remote desert to evacuate 150 civilians stranded in the country's southern oilfields, Defence Minister Liam Fox said.
Libya's foreign legion of domestic helpers, construction workers and oil executives were among thousands scrambling to evacuate by air, land and sea.
More than 38,000 people have fled through the Ras Jedir crossing on Libya's western, Tunisian border alone, an official there told AFP.
The UN World Food Programme warned on Friday that the food distribution system was "at risk of collapsing" in a mainly desert nation which is heavily dependent on imports.