TOBRUK, Libya (AP) - Moammar Gadhafi vowed to launch a final assault on the opposition's capital Benghazi and crush the rebellion as his forces advanced toward the city and warplanes bombed its airport Thursday. In the face of Gadhafi's increasingly powerful offensive, the United Nations was to vote on a mandate Washington seeks 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 change 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 Thursday evening, 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."
"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 80 miles 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. Mohammed Abdel-Rahman, a 42-year-old merchant who lives nearby, said he saw one of the warplanes shot down after striking Benina - a civilian and military air facility about 12 miles from the center of the city. He said the strikes caused light damage.
Another witness, medical official Qassem al-Shibli, told The Associated Press that he saw three planes attack the airport and nearby rebel military camps before two were shot down. A third witness saw fire trucks fighting a blaze at the airport, and black smoke billowing from the area. Another witness reported that a rebel warplane crashed north of Benghazi, apparently after running out of fuel.
At the same time, the rebels were sending their own warplanes in an attempt to break the regime's assault on Ajdabiya, a city about 100 miles southwest of Benghazi that has been under a punishing siege by Gadhafi's forces the past two days. Three rebel warplanes and helicopters struck government troops massed at Ajdabiya's western gates, said Mustafa Gheriani, a spokesman in Benghazi, and Abdel-Bari Zwei, an opposition activist in Ajdabiya.
But by Thursday afternoon, Gadhafi's army were holding the southern, eastern and western outskirts of Ajdabiya. Further outflanking the rebels, troops landing from sea swept into the nearby Mediterranean port town of Zwitina, 15 miles north, between Ajdabiya and Benghazi.