The UN Security Council has voted unanimously to impose sanctions on Muammar Gaddafi's Libyan regime for its attempts to put down an uprising.
It backed an arms embargo and asset freeze while referring Colonel Gaddafi to the International Criminal Court for alleged crimes against humanity.
US President Barack Obama has said the Libyan leader should step down and leave the country immediately.
He still controls Tripoli, but eastern Libya has fallen to the uprising.
Discussions on forming an anti-Gaddafi transitional government are reportedly under way.
Mustafa Abdel-Jalil - who resigned as justice minister in protest against the excessive use of force against demonstrators - said a body comprising military and civilian figures would prepare for elections within three months, Libya's privately-owned Quryna newspaper reported.
Libya's ambassadors to the United States and UN have both reportedly voiced their support for the plan, which was being discussed in the rebel-controlled eastern town of Benghazi.
The UN estimates more than 1,000 people have died as Col Gadddafi's regime attempted to quell the 10-day-old revolt.
Saturday night's vote was only the second time the Security Council has referred a country to the ICC, and the first time such a vote has been unanimous.
Afterwards, Libya's deputy UN envoy said the sanctions would give "moral support" to the anti-Gaddafi protesters.
"[The sanctions] will help put an end to this fascist regime which is still in existence in Tripoli," said Ibrahim Dabbashi, who declared his opposition to Col Gaddafi at the start of the week.
The Libyan delegation at the UN had sent a letter to the Council backing measures to hold to account those responsible for armed attacks on Libyan civilians, including action through the International Criminal Court - which had been one of the main points of contention in the resolution.
The US has already imposed sanctions against Libya, and closed its embassy in Tripoli.
Australia says it will place sanctions on 22 individuals in Col Gaddafi's inner circle, barring financial transactions and their entry to Australia.
Foreign Minister Kevin Rudd said the move was a "concrete demonstration of Australia's support for the people of Libya".
Struggle for control
On Saturday, one of Col Gaddafi's sons, Saif al-Islam, insisted normal life was continuing in three-quarters of Libya. By contrast, anti-Gaddafi forces say they control 80% of the country.
The claims are difficult to verify but it is known that anti-Gaddafi forces control Benghazi, Libya's second city, while the long-time leader still controls most of the capital, Tripoli, home to two million of the country's 6.5 million population.
Tripoli was calm on Saturday, with shops open and people on the streets. Supporters of Col Gaddafi reportedly occupied central Green Square in a public show of support for the beleaguered leader.
However, in the working-class area of Tajoura, scene of protests in previous days, residents set up makeshift roadblocks composed of rocks, concrete blocks and even chopped-down palm trees in an effort to stop vehicles carrying armed Gaddafi loyalists from entering the neighbourhood.
Outside the capital, anti-Gaddafi protesters were consolidating their power in Benghazi, with leaders of the uprising establishing committees to run the city and deliver basic services.
Rebels were reportedly fighting units of the regular army in the western cities of Misrata and Zawiya on Saturday.
Thousands of foreign nationals - many of them employed in the oil industry - continue to be evacuated from the country by air, sea and land.
On Saturday, two British military transport aircraft picked up about 150 foreign nationals in the desert south of Benghazi and flew them to the Mediterranean island of Malta.
Britain also announced it had temporarily closed its embassy in Tripoli and pulled out its staff on the last UK government-chartered aircraft because of the deteriorating security situation.
Some 10,000 people remain outside Tripoli airport's terminal building and several thousand more are inside, says BBC Middle East editor Jeremy Bowen, who saw piles of discarded luggage abandoned by people desperate to flee the country.
Most of those trying to leave were Egyptians, many of whom had been waiting at the airport for several days.
Thousands of Egyptians have also been streaming out of Libya over the western border to Tunisia.
The BBC's Jim Muir, on the Tunisian side of the border, says the workers face an appalling situation, with no resources to move on and no sanitary facilities.
He says the Tunisian army aims to relocate the workers to camps but this could take weeks.
And the Tunisian government installed after Presiden Zine Abidine Ben Ali was deposed in January is preoccupied with its own affairs, our correspondent says. There were renewed anti-government protests in Tunis on Saturday in which three people were killed.