US President Barack Obama lays a wreath at the 9/11 Memorial in New York on May 5, 2011. Obama took a defiant message to the New York epicenter of the 9/11 attacks Thursday, warning that Osama bin Laden's death proved America will never fail to bring terrorists to "justice." AFP PHOTO/Jewel Samad (Photo credit should read JEWEL SAMAD/AFP/Getty Images) (JEWEL SAMAD/AFP/GETTY IMAGES)

The U.N. Security Council voted Thursday to authorize “all necessary measures” to protect civilians in Libya, and European backers of the resolution said enforcement actions could follow within hours.

The resolution passed 10 to 0 with 5 abstentions. It demands an immediate cease-fire in Libya, “the complete end of violence and all attacks against and abuse of civilians,” and it authorizes the international community to impose a no-fly zone.

The vote took place as the window for action closed in Libya, with forces loyal to leader Moammar Gaddafi advancing toward Benghazi, the rebel headquarters in eastern Libya, and renewing attacks on remaining opposition-held towns in the west.

Before the vote, the United States had added its sponsorship to the resolution authored by France, Britain and Lebanon. Russia, China and Germany, all of whom have opposed intervention in varying degrees, abstained from the vote.

The resolution establishes “a ban on all flights in the airspace” of Libya except for humanitarian and evacuation flights.

Secretary of State Hillary Rodham Clinton, speaking during a visit to Tunisia, said that a no-fly zone would “require certain actions taken to protect the planes and the pilots, including bombing targets like the Libyan defense systems.”

A French foreign ministry official said France and Britain, with cooperation from one or two Arab countries, would be prepared to start carrying out a resolution as soon as it was approved, within a matter of hours. NATO planners this week presented alliance political leaders with final plans for various military options in Libya.

The United States has five warships off the Libyan coast in the Mediterranean, and it was unclear what role, if any, U.S. forces would play in any initial enforcement actions. The French official, who spoke anonymously under conditions laid out by the foreign ministry, said Britain and France were prepared to act without U.S. direct participation, or with a limited U.S. role.

Italy last week told NATO that its land bases could be used for enforcement of a no-fly zone.

Although NATO has been planning for possible action in Libya as a group, the resolution authorizes action by U.N. members “acting nationally or through regional organizations,” and France has said its air forces would be ready to commence operations — most likely targeting runways and air defenses — as early as Thursday evening. Britain has also expressed interest, but has made no official statement.

A senior NATO official expressed some consternation at France’s eagerness, and said French forces were unlikely to take full-scale action until at least Saturday. “On the NATO side,” the official said, speaking on condition of anonymity, “we’re not yet ready” and the alliance has not formally approved plans for a specific operation. But “we could move within days,” he said.

Although the Pentagon has participated in NATO planning, the U.S. military has not yet made final decisions nor has the White House approved any specific American actions. “I don’t think we’re there yet,” a U.S. official said, noting that the United States can “do things the French can’t,” including the use of B-2 bombers and cruise missiles.

Ninety miles southwest of Benghazi, rebel fighters near the the oil town of Zuwaytinah said they were losing ground to Gaddafi’s forces.

“Early this morning they took it over,” said Mohamed Ibraiq, 23, a fighter, referring to key intersection that had been the rebels’ front line.

Zaruq Fawsi Falaq, 29, another fighter, said he and other rebel fighters attempted to fight off Gaddafi’s forces, but came under heavy tank and artillery fire. “Eight pickup trucks filled with our fighters disappeared,” said Falaq. “Up to now, we don’t know what happened to them. We were forced to move back.”

Rebel spokesman Essam Gheriani reiterated appeals for intervention.

“We have passed the point of announcements and declarations,” he said. “What we really need now is action by the international community.”

Gheriani said that a no-fly zone would no longer stop the march of Gaddafi’s military, and that targeted air strikes would be most effective at this stage of the rebellion.

“Our demand for a no-fly zone would have been sufficient two weeks ago,” Gheriani said. “Now the need is to hit Gaddafi’s land troops and tanks that are laying siege to Libyan cities and stop their advance toward Benghazi. Time is in his favor, not ours.”

Rapid movement at the United Nations contrasted with continued delays during the past several weeks in formulating an international response to the crisis as Gaddafi launched his counterattack against rebel forces.

As the United Nations moved toward a decision, Libya’s defense ministry broadcast a statement saying it would strike back at civilian and foreign targets if the country comes under attack from foreign forces, Reuters reported from Tripoli.

“Any foreign military act against Libya will expose all air and maritime traffic in the Mediterranean Sea to danger and civilian and military [facilities] will become targets of Libya’s counter-attack,” the statement said. “The Mediterranean basin will face danger not just in the short-term but also in the long term.”

As Security Council representatives consulted in New York, the United States and its European allies pushed for Arab participation in the intervention. Before the vote, U.N. diplomats said that they believed that Russia and China were persuaded not to oppose the resolution following the Arab League’s endorsement last weekend of a no-fly zone and after wording was added to the document ruling out an “occupation” force on the ground.

Several Arab governments are believed to have agreed to participate in the action, most likely with financial backing and possibly with liaison officers as part of a command and control facility.

At a Senate hearing, Undersecretary of State William J. Burns agreed that actions would “include a no-fly zone but could go beyond them,” to include targeted air strikes, jamming of government communications signals and handing over internationally frozen Libyan government assets, including $32 billion in the United States alone, to the rebel leadership.

Burns confronted sharply differing views about the Libyan crisis that crossed party lines. Some, led by Sen. John F. Kerry (D-Mass.), charged the administration has been too cautious in its response.

“Time is running out for the Libyan people,” he said.

But Sen. Richard Lugar (R-Ind.), along with several committee Democrats, warned of the “risk that our involvement would escalate” and said the administration should “seek congressional debate on a declaration of war” against Libya before U.S. forces participate in any action.

Raghavan reported from Sidi Abd el-Ati, Libya, and Lynch from the United Nations.