BIN JAWWAD, Libya - Rebel forces on Monday fought their way to the doorstep of Muammar Qaddafi's hometown of Sirte, a key government stronghold guarding the road to the capital Tripoli, their rapid advance built on powerful international airstrikes that have battered Qaddafi's air force, armor and troops.
The rebels' offensive has restored to the opposition all the territory they lost over the past week and brought them closer than ever to Sirte, with their fighters advancing to within 60 miles of the bastion of Qaddafi's power in the center of the country.
But the advance on Sirte and the flip-flop in the conflict's momentum brought into sharper relief the central ambiguity of the international mission in Libya. When Qaddafi's forces were besieging rebel-held cities in the east last week, allied airstrikes on his troops more directly fit into the U.N. mandate of protecting civilians. But those same strikes have now allowed rebels to go on the assault.
Russia on Monday criticized the international campaign, saying it had overstepped its U.N. mandate to protect civilians and had taken sides in a civil war.
NATO's commander for the operation, Lt. Gen. Charles Bouchard of Canada, said his mission was clear, saying every decision was designed to prevent attacks on civilians. "Our goal is to protect and help the civilians and population centers under the threat of attack," he said.
But in Brussels, NATO spokeswoman Oana Lungescu noted that the allied operation was launched in response to "the systematic attacks by Col. Qaddafi against his own people."
"That is how this all started, we have to remember that," she said.
Meanwhile, a French military spokesman said French aircraft struck a Libyan military command center south of the capital, Tripoli. Col. Thierry Burkhard said the Mirage fighter jet carried out the airstrike on the military complex and command center more than six miles south of Tripoli and used by forces loyal to Qaddafi.
Some residents were fleeing Sirte, as soldiers from a brigade commanded by Qaddafi's son al-Saadi and allied militiamen streamed to positions on the city's outskirts to defend it, witnesses said. Sirte -- where a significant air and military base is located -- was hit by airstrikes Sunday night and Monday morning, witnesses said, but they did not know what was targeted.
The city of 100,000 is crucial both for its strategic position and its symbolic value. Over the years, Qaddafi has made it effectively Libya's second capital, building up what had been a quiet agricultural community with lavish conference halls where Arab and African summits were held. The city is dominated by members of the Libyan leader's Gadhadhfa tribe, but many in another large Sirte tribe -- the Firjan -- are believed to resent his rule, and rebels are hoping to encourage them and other tribes there to rise up to help in their capture of the city.
Its fall to the rebels would largely open their way to move on the capital, Tripoli, 250 miles to the northwest along the Mediterranean coast.
About halfway between the two lies Libya's third largest city, Misrata, which has been in rebel hands since early on in the nearly month-and-a-half-old uprising but has been under heavy siege by Qaddafi forces for weeks. Misrata came under renewed heavy shelling on Monday, witnesses said. There is little but empty desert highway and a few small hamlets between Sirte and Misrata.
Gamal Mughrabi, a 46-year-old rebel fighter, said there are both anti- and pro-Qaddafi forces inside Sirte and predicted a tough fight. "Qaddafi is not going to give up Sirte easily because straightaway after Sirte is Misrata, and after that it's straight to Qaddafi's house," he said. "So Sirte is the last line of defense."
In a symbolic diplomatic victory for the opposition, the tiny state of Qatar recognized Libya's rebels as the legitimate representatives of the country -- the first Arab state to do so.
CBS News correspondent Mandy Clark, who was in the key oil port of Ras Lanouf when it fell to Qaddafi's forces two weeks ago, was back on Sunday as rebels retook the strategic city. Coalition planes slammed the government forces' tanks and other machinery on the outskirts, enabling rebels to reclaim the territory.
Rebel leaders in Ras Lanouf, about 130 miles east of Sirte, told CBS News that government forces were on the run, but they're not chasing them this time. Instead, the rebels were conducting clearing operations to secure the ground they fought hard to win back.
Libya's rebels have recovered hundreds of miles of flat, uninhabited territory at record speeds after Qaddafi's forces were forced to pull back by the strikes that began March 19. When the first strikes were launched, regime troops were deep in the rebel-held territory, storming toward the opposition capital of Benghazi, 370 miles east of Sirte.
A rebel commander among the fighters advancing on Sirte acknowledged that their offensive would not have been possible without the strikes, which he said had evened the two sides' firepower.
"Now because of NATO strikes on (the government's) heavy weapons, we're almost fighting with the same weapons, only we have Grad rockets now and they don't," said Gen. Hamdi Hassi at the small town of Bin Jawwad, just 18 miles from the front.
The U.S. launched six Tomahawk missiles Sunday and early Monday from navy positions in the Mediterranean Sea, two defense officials said Monday on condition of anonymity because they were not yet authorized to release the information.
That brought to 199 the number of the long-range cruise missiles fired by international forces in the campaign, one official said.
International air forces flew 110 missions late Sunday and early Monday -- 75 of them strike missions. Targets included Qaddafi ammunition stores, air defenses and ground forces, including vehicles and tanks, a third official said.