In the face of Gadhafi's increasingly powerful offensive, the United Nations Security Council passed a resolution to strike his forces on land, sea and air.
After weeks of hesitancy over imposing a no-fly zone in Libya, the United States made a dramatic about-face, calling for even more expanded action, including strikes on Gadhafi's ground forces besieging rebel-held cities.
The Security Council voted in New York in favour of a resolution that would open the way for that, establishing a no-fly zone but also authorising member states to "take all necessary measures" to protect civilians from attacks by Gadhafi's forces, but ruling out a "foreign occupation," meaning a ground offensive.
In Benghazi, the main rebel stronghold, a large crowd watching the vote on an outdoor TV projection burst into celebration as green and red fireworks burst in the air, as broadcast live on the Al-Jazeera satellite TV channel.
A top official of the rebels' transitional national council, Ali al-Essawi, welcomed the resolution. "We think that this resolution ... will mark the end of the impunity and dictatorship of Gadhafi," he told The Associated Press in the Benghazi.
In Tobruk, east of Benghazi, happy Libyans fired weapons in the air to celebrate the vote.
In contrast, a dentist in the capital of Tripoli rejected the measure. "You are in fact protecting people carrying weapons against the official forces. This is nonsense," said Mohammed Salah, 33.
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 UN-sponsored attacks. "If the world is crazy, we will be crazy too, he said.
Speaking to reporters in Tripoli after the vote, Libyan Deputy Foreign Minister Khalid Kaim took a conciliatory tone, offering to negotiat a cease-fire with the rebels.
He welcomed the Security Council's endorsement of the territorial unity of Libya and concern for its citizens, but called on the world not to allow them to receive weapons. because "if any countries do that, they will be inviting Libyans to kill each other."
The shift toward international action reflected the past week's swift reversal of the realities on the ground, where once-confident rebels are now in danger of being crushed under 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, Libya's second largest city and the headquarters of the opposition's leadership.
In an address, Gadhafi proclaimed that the "hour of decision has come" and that his regime would begin "tonight" to put an end to the rebellion.
"The matter has been decided ... we are coming," he said, calling in by telephone to state TV and addressing the people of Benghazi. "There is amnesty for those who throw away their weapons and sits in their house ... No matter what they did in the past, (it's) forgiven," he said.
But for those who resist, he said, "there will be no mercy or compassion."
Gadhafi says his forces would "rescue" the people of Benghazi from "traitors" and warned them not to stand alongside the opposition.
"This is your happy day, we will destroy your enemies," he said. "Prepare for this moment to get rid of the traitors. Tomorrow we will show the world, to see if the city is one of traitors or heroes ... Don't betray me, my beloved Benghazi."
The closest known position of Gadhafi's ground forces from Benghazi was still about 130km to the south, making it unclear if they would move on the city Thursday night as Gadhafi boasted. But during the day, several regime warplanes bombed the city's Benina Airport.
Several witnesses said rebels in Benghazi succeeded in shooting down at least two of the attacking aircraft.
