The U.N. Security Council voted Thursday to authorize military action, including airstrikes against Libyan tanks and heavy artillery and a no-fly zone, a risky foreign intervention aimed at averting a bloody rout of rebels by forces loyal to Moammar Gadhafi.
The Security Council authorized member nations to take "all necessary measures" to protect civilians, diplomatic code words calling for military action.
Diplomats said the resolution — which passed with 10 votes, including the United States, and abstentions from Russia, China, Germany, Brazil and India — was written in sweeping terms to allow for a wide range of actions, including strikes on air-defense systems and missile attacks from ships. Military activity could get under way within a matter of hours, they said.
The Associated Press, however, reported that unnamed U.S. officials, speaking after a closed-door briefing in Congress, said they expected an attempt to ground Gadhafi's air force could begin by Sunday or Monday and would probably involve jet fighters, bombers and surveillance aircraft.
Speaking on a radio call-in show in Tripoli on Thursday, Gadhafi raised the level of urgency on the vote, saying that his forces would begin an assault on Benghazi that night.
"We will come house by house, room by room. It's over. The issue has been decided," he said, offering amnesty to those who laid down their arms.
He also dismissed any action by the Security Council.
"We don't acknowledge their resolutions," he said. He pledged to respond harshly to U.N.-sponsored attacks. "If the world is crazy, we will be crazy too,'' he said.
"It's going to be tougher to stop Gadhafi today than it was a week ago," said James M. Lindsay, the director of studies at the Council on Foreign Relations. "The issue is not going to be settled in the skies above Benghazi, but by taking out tanks, artillery positions and multiple-launch rocket systems on the ground."
Lindsay said that would require helicopter gunships and other close-in support aircraft rather than advanced fighter planes. Other analysts said repelling Gadhafi's forces might require ground troops, an option that has been flatly ruled out by Secretary of State Hillary Rodham Clinton and other senior American officials.
The New York Times, citing an unnamed Pentagon official, reported that decisions were still being made about what kind of military action, if any, the United States might take with the allies against Libya. U.S. support is likely to consist of much of what the United States already has in the region — AWACS radar planes to help with air traffic control should there be airstrikes, other surveillance aircraft and about 400 Marines aboard two amphibious assault ships in the region, the Kearsarge and the Ponce, the newspaper reported.
The Americans could also provide signal-jamming aircraft in international airspace to muddle Libyan government communications with its military units.
The New York Times also reported that officials in Britain, France and the United States were all adamant that Arab League forces take part in the military actions and help pay for the operations, and that it not be led by NATO, to avoid the appearance that the West was attacking another Muslim country.
The resolution also called for an immediate cease-fire and tightened sanctions against the Libyan regime by expanding an asset freeze that the United States has already used to sequester more than $32 billion linked to Gadhafi and his inner circle.
Characterizing Gadhafi as a menacing "creature" lacking a moral compass, Clinton said Thursday that the international community had little choice but to act.
"There is no good choice here. If you don't get him out and if you don't support the opposition and he stays in power, there's no telling what he will do," Clinton said from Tunisia.
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 and 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. His ground forces were still about 80 miles south of the city on Thursday evening Libya time, so it was unclear whether they would move on the city as quickly as he suggested.
Libyan officials were also vowing to retake Misrata, the last rebel-held city in the western half of the country, which has been sealed off by Gadhafi troops in a blockade that has cut off most water and food supplies for days, residents said.
Information from New York Times, Associated Press and McClatchy Newspapers was used in this report.