The UN Security Council on Thursday voted to ban flights in Libya's airspace and authorised military action to implement the ban, triggering intervention by individual countries and organizations like Nato.
But the council explicitly ruled out any occupation force in Libya.
The 15-nation council voted 10-0 to authorize the no-fly zone. China, Brazil, India, Germany and Russia abstained. The measure was backed by Bosnia, Colombia, France, Gabon, Lebanon, Nigeria, Portugal, South Africa, Britain and the US.
China and Russia are permanent members of the council and their abstentions allowed the resolution to be adopted. If they had cast a negative vote, or a veto, the resolution would have been killed.
The three other permanent members with veto power, the US, France and Britain, voted in favour.
Germany's UN ambassador Peter Wittig told the council after the vote that the military option was 'extremely difficult' for Berlin to support because it may involve the UN in a military situation in Libya.
Wittig, like other countries that abstained, said sanctions and financial measures may achieve the same result in bringing down Libyan leader Muammar Gaddafi, who they said had already lost legitimacy to rule over the country.
US ambassador Susan Rice, whose government had not overtly supported the no-fly zone, voted in favour, saying, "The council has responded to the cries of the Libyan people for help."
The council also demanded an immediate ceasefire, which together with the no-fly zone would constitute actions to protect civilians against Gaddafi's forces, including aerial bombing.
Gaddafi had earlier on Thursday warned on national radio of a bloodbath in the opposition stronghold of Benghazi if rebels do not give up their arms. Gaddafi threatened to unleash his forces on the eastern Libyan city in a matter of hours.
Gaddafi's military has also threatened retaliation against forces in the Mediterranean Sea for any foreign intervention in the country.
"All military and civilian air and sea vessels in the Mediterranean Sea will become targets of the Libyan retaliation," a spokesperson for the military told Libyan media.
French foreign minister Alain Juppe, in New York to push for passage, vowed before the vote that France was prepared to act almost immediately.
Juppe said his country, Britain, some Arab countries and possibly the US were "ready to take action" to implement the resolution.
"We cannot abandon the civilians in Libya," Juppe said just before the vote.
"France wants to contribute all its strengths with the US, Britain and others to implement the resolution and the no-fly zone is the only means to protect the civilians."
The council demanded the Libyan regime put an end to all attacks and abuses of civilians and comply with international humanitarian law, human rights and refugee law and protect civilians.
The authorisation to use 'all necessary means' to implement the resolution implies unilateral action by countries or in coordination with organisations to implement the no-fly zone.
The phrase 'all necessary means' implies use of military force to implement the so-called no-fly zone, which had been the topic of discussion in the past two weeks.
Individual countries or organisations that plan to implement the no-fly zone are called to notify the UN secretary general and the League of Arab States before taking action. The League on March 12 supported the no-fly zone as a way to stop the killing of civilians by Gaddafi's forces.
The League of Arab States was asked to coordinate with the UN secretary general on the measures they are taking to implement the ban.
The arms embargo imposed on Libya by the council on Feb 26 was modified to allow actions by individual countries or organizations to inspect in their territories, including seaports, airports and on the high seas, all vessels and aircraft bound to and from Libya if there are reasonable grounds to believe that they are carrying weapons and military materials.
Mercenaries currently assisting Gaddafi's forces are also subject to the arms embargo.
Aircraft registered in Libya, owned or operated by Libyan nationals, and their companies are prohibited to take off or land, or overfly in other countries or territories unless those flights are authorised by a UN committee, including in emergency cases.
The freeze of assets ordered on February 26 was expanded from six to 13 people, including Gaddafi and his immediate family members, and six entities, including the Central Bank of Libya, Libyan Foreign Bank and Libyan National Oil Company.