Libya declared an immediate cease-fire and promised to stop military operations Friday in a bid to fend off international military intervention after the U.N. authorized a no-fly zone and ``all necessary measures'' to prevent the regime from striking its own people.

 The announcement by Foreign Minister Moussa Koussa followed a fierce attack by Gadhafi's forces against Misrata, the last rebel-held city in the western half of the country. A doctor said at least six people were killed.

 The U.N. Security Council resolution, which was passed late Thursday after weeks of deliberation, set the stage for airstrikes, a no-fly zone and other military measures short of a ground invasion. Britain announced that it would send fighter jets and France was making plans to deploy planes, but the U.S. had yet to announce what its role would be. NATO also held an emergency meeting.

   With the international community mobilizing, Koussa said the government would cease fire in line with the resolution, although he criticized the authorization of international military action, calling it a violation of Libya's sovereignty.

   ``The government is opening channels for true, serious dialogue with all parties,'' he said during a news conference in Tripoli, the capital.
   The attack on Misrata, Libya's third-largest city, came as the rebels were on the defensive in their eastern stronghold after Gadhafi vowed to launch a final assault and crush the nearly 5-week-old rebellion against him.

   The opposition expressed hope the U.N. resolution would help turn the tide in their favor after days of fierce fighting.

   ``We think Gadhafi's forces will not advance against us. Our morale is very high now. I think we have the upper hand,'' Col. Salah Osman, a former army officer who defected to the rebel side, said. He was speaking at a checkpoint near the eastern town of Sultan.

   The Western powers faced pressure to act urgently after weeks spent deliberation over what to do about Gadhafi as his regime gained momentum. The U.S. has positioned a host of forces and ships in the region, including submarines and destroyers and amphibious assault and landing ships with some 400 Marines aboard. It also could provide a range of surveillance assets.

   In an interview with Portuguese television broadcast just before the U.N. vote, Gadhafi pledged to respond harshly to U.N.-sponsored attacks. ``If the world is crazy,'' he said, ``we will be crazy, too.''

   The Libyan government closed its airspace to all traffic Friday, according to Europe's air traffic control agency, Eurocontrol.

   Government tanks rolled into Misrata, 125 miles (200 kilometers) southeast of Tripoli, early Friday, shelling houses, hospitals and a mosque for several hours before pulling back to the city's outskirts, witnesses said. At least six people were killed, raising the total death toll in two days of fighting to nine, a local doctor said.

   Misrata is the last rebel holdout in the western half of the country after Gadhafi recaptured a string of other cities that had fallen to the opposition early in the uprising that began Feb. 15.

Its fall would leave the country largely divided, with the rebels bottled up in the east near the border with Egypt.

   The city has been under a punishing blockade that has prevented aid ships from delivering medicine and other supplies, the doctor said.
   ``They haven't stopped shelling us for a week _ we sleep to shelling, and wake up to shelling. They are targeting houses and hospitals,'' he said, adding the hospital had been overwhelmed.

   ``We have had to perform surgeries in the hallways using the light from our cell phones to see what we're doing. We are also using some clinics around the town, some only have 60 beds, which isn't enough,'' he said.

   Another doctor claimed Gadhafi's forces had surrounded some neighborhoods and were shooting at people who ventured out of their homes. ``Militias used two ambulances to jump out of and shoot at innocent people indiscriminately,'' he said.

   The situation appeared to be calm in Benghazi.

   Col. Osman said Gadhafi's forces had surrounded the nearby city of Ajdabiya, but rebels remained inside.

   The shift toward international action reflected dramatic change on the ground in Libya in the past week. The rebels, once confident, found themselves in danger of being crushed by an overpowering pro-Gadhafi force using rockets, artillery, tanks, warplanes. That force has advanced along the Mediterranean coast aiming to recapture the rebel-held eastern half of Libya.

   Gadhafi troops encircled the city of Ajdabiya, the first in the path of their march, but also had some troops positioned beyond it toward Benghazi, the second largest Libyan city, with a population of about 700,000.

   A large crowd in Benghazi was watching the vote on an outdoor TV projection and burst into cheers, with green and red fireworks exploding overhead. In Tobruk, east of Benghazi, happy Libyans fired weapons in the air to celebrate the vote.

   Libya's unrest began in Benghazi and spread east to Tripoli. Like others in the Mideast, the uprising started with popular demonstrations against Gadhafi, rejecting his 41 years of despotic and often brutal rule. The tone quickly changed after Gadhafi's security in Tripoli forcefully put down the gatherings there.

   Soon rebel forces began arming themselves, quickly taking control of the country's east centered on Benghazi. Some Libyan army units joined the rebels, providing them with some firepower, but much less than Gadhafi's remaining forces.

   There are no reliable death tolls. Rebels say more than 1,000 people have been killed in a month of fighting, while Gadhafi claims the toll is only 150.

UNITED NATIONS (AP) _ The U.N. Security Council voted Thursday to impose a no-fly zone over Libya and authorize ``all necessary measures'' to protect civilians from attacks by Moammar Gadhafi's forces, hours after the Libyan leader vowed to crush the rebellion with a final assault on the opposition capital of Benghazi.

The U.N. vote paved the way for possible international air strikes on Gadhafi's advancing military and reflected the past week's swift reversal of the situation in Libya, where once-confident rebels are now in danger of being obliterated by an overpowering pro-Gadhafi force using rockets, artillery, tanks, warplanes. That force has advanced along the Mediterranean coast aiming to recapture the rebel-held eastern half of Libya.

The resolution establishes ``a ban on all flights in the airspace of the Libyan Arab Jamahiriya in order to help protect civilians.''

It also authorizes U.N. member states to take ``all necessary measures ... to protect civilians and civilian populated areas under threat of attack in the Libyan Arab Jamahiriya, including Benghazi, while excluding a foreign occupation force of any form on any part of Libyan territory.''

The vote was 10-0 with five countries abstaining including Russia and China, which have veto power in the council, along with India, Germany and Brazil. The United States, France and Britain pushed for speedy approval.

In Benghazi, Al-Jazeera satellite TV channel showed a large crowd watching the vote on an outdoor TV projection burst into celebration as green and red fireworks exploded in the air.

In an interview broadcast just before the Security Council voted, Gadhafi dismissed its actions. ``The U.N. Security Council has no mandate. We don't acknowledge their resolutions,'' he told the Portuguese public Radiotelevisao Portuguesa. He pledged to respond harshly to U.N.-sponsored attacks. ``If the world is crazy, we will be crazy too,'' he said.

U.S. officials have said the authorization for ``all necessary measures'' provides a legal basis for countries to carry out air strikes to protect civilians from Gadhafi's forces.

``We had said all along that Gadhafi must go,'' said British Foreign Secretary William Hague. ``It is necessary to take these measures to avoid greater bloodshed.''

In Britain, a lawmaker with knowledge of defense matters confirmed that British forces were on stand by for air strikes and could be mobilized as soon as Thursday night. The lawmaker declined to be named because the Defense Ministry has not issued official confirmation.

French Prime Minister Francois Fillon told France-2 Television that if the resolution was approved France would support military action against Gadhafi within a matter of hours.

Immediately before the vote, France's Foreign Minister Alain Juppe urged adoption of the resolution saying sanctions imposed by the Security Council on Feb. 26 aren't enough and ``violence against the civilian population has been redoubled.''

``We cannot let these warmongers ... do this,'' he said. ``We have very little time left. It's a matter of days. It's perhaps a matter of hours. We should not arrive too late.''

The resolution also calls for stronger enforcement of the arms embargo, adds names of individuals, companies and other entities to the list of those subject to travel bans and asset freezes, and requires all countries to ban Libyan flights from landing, taking off or overflying their country.

It also demands that Libya ensure the ``rapid and unimpeded passage of humanitarian assistance'' and asks U.N. Secretary-General Ban Ki-moon to establish an eight-member panel of experts to assist the Security Council committee in monitoring sanctions.

Russia and China had expressed doubts about the United Nations and other outside powers using force against Gadhafi, a view backed by India, Brazil and Germany who also abstained.

Germany's U.N. Ambassador Peter Wittig expressed fear that using military force could lead to ``the likelihood of large-scale loss of life.''

Despite the lack of consensus, U.S. Ambassador Susan Rice said: ``Today the Security Council has responded to the Libyan people's cry for help.''

She said ``Colonel Gadhafi and those who still stand by him continue to grossly and systematically abuse the most fundamental of the human rights of his people.''

Gadhafi, in the Radiotelevisao Portuguesa interview, said that he rejected any U.N. threats of action.

``The U.N. Security Council has no mandate,'' Gadhafi said. ``We don't acknowledge their resolutions.''

He warned that any military action would be construed as ``colonization without any justification'' and would have ``grave repercussions.''

The Arab League has supported the call for a no-fly zone, and Gadhafi said that as a result ``it's finished.''

The United States joined the resolution's initial supporters _ Britain, France and Lebanon _ not only in pushing for a speedy vote but also in pressing for action beyond creation of a no-fly zone to protect civilians from air, land and sea attacks by Gadhafi's fighters.

This marked a dramatic about-face by the Obama administration which for weeks hesitated about supporting a no-fly zone, fearing that the United States could get sucked into another war in a Muslim nation.

U.S. Secretary of State Hillary Clinton told reporters in Tunisia on Thursday that a U.N. no-fly zone over Libya would require action to protect the planes and pilots, ``including bombing targets like the Libyan defense systems.'' She said no ground intervention is being considered.

Michael Mann, a spokesman for EU foreign policy chief Catherine Ashton, called the situation ``very worrying'' and said the EU was looking to the U.N. Security Council before making further decisions. ``We have always said all along that we are planning for all options,'' he said.

Russia's U.N. Ambassador Vitaly Churkin, whose government had expressed misgivings about a no-fly zone, proposed that the council vote first on a resolution calling for a cease-fire in Libya. The council refused but added a paragraph in the resolution calling for an immediate cease-fire ``and a complete end to violence and all attacks against, and abuses of, civilians.''

France and Britain failed to win support for a no-fly zone during a two-day meeting of Group of Eight foreign ministers in Paris on Tuesday and the G-8's final communique did not mention a flight ban, leaving any action to the Security Council.