By Angus MacSwan
ROAD TO BREGA, Libya (Reuters) - Libyan rebels reached the oil terminal town of Brega on Sunday after routing government forces from a strategic eastern town, as Muammar Gaddafi's troops pounded the main rebel stronghold in the west.
Rebel fighters moved unchallenged into Brega and Al Jazeera television said they then pushed further west to the edge of Uqayla, the only town between them and major oil port Ras Lanuf.
The speed of the rebel advance suggests a rapid retreat by Gaddafi's forces after they lost Ajdabiyah, an important gateway for the better-armed force to the rebel-held east.
Rebels took Ajdabiyah after Western warplanes bombed the Gaddafi forces in what has become by far the most violent popular revolt in two months of bloody Arab world unrest.
The rebels' advance follows two weeks of losses and indicates that Western air strikes are shifting the battlefield dynamics in their favor.
As the front-line moved in the east, Gaddafi forces in the west pounded Misrata with tank, mortar and artillery fire on Saturday, although the shelling halted after coalition aircraft appeared overhead, rebels said.
"He pulled his forces out of Ajdabiyah and Brega so that he puts all his weight into attacking Misrata and winning so he can control the whole west versus losing the whole east," a rebel, called Saadoun, told Reuters by telephone on Sunday.
France said its warplanes destroyed five Libyan aircraft and two helicopters at an air base outside Misrata on Saturday.
Libyan government spokesman Mussa Ibrahim told reporters in the capital Tripoli that Gaddafi was directing his forces but appeared to suggest the leader might be moving around the country so as to keep his whereabouts a mystery.
"He is leading the battle. He is leading the nation forward from anywhere in the country," said Ibrahim.
"He has many offices, many places around Libya. I assure you he is leading the nation at this very moment and he is in continuous communication with everyone around the country."
Asked if Gaddafi was constantly on the move, Ibrahim said: "It's a time of war. In a time of war you act differently."
Capturing Ajdabiyah, a gateway from western Libya to the rebel stronghold of Benghazi and the oil town of Tobruk, was a big morale boost for the rebels a week after coalition air strikes began to enforce a U.N.-mandated no-fly zone.
In Ajdabiyah, rebel fighters danced on tanks, waved flags and fired in the air near buildings riddled with bullet holes. Half a dozen wrecked tanks lay near the eastern entrance to the town and the ground was strewn with empty shell casings.
Rebels said fighting had lasted through Friday night into Saturday. By the town's western gate there were bodies of more than a dozen of Gaddafi's fighters. An abandoned truckload of ammunition suggested his forces had beaten a hasty retreat.
"Thank you Britain, thank you France, thank you America," said one rebel, praising Western air strikes.
The French armed forces said around 20 French aircraft supported by an AWACS surveillance plane struck targets in Misrata during the day on Saturday, including five Galeb fighter jets and two MI-35 helicopters on the ground outside Misrata.
Last week Libyan officials said nearly 100 civilians had been killed in the coalition strikes.
U.S. Defense Secretary Robert Gates dismissed the assertion on Saturday, saying: "The truth of the matter is we have trouble coming up with proof of any civilian casualties that we have been responsible for."
"We do have a lot of intelligence reporting about Gaddafi taking the bodies of the people he's killed and putting them at the sites where we've attacked," Gates told CBS News' "Face the Nation with Bob Schieffer."
U.S. President Barack Obama, criticized by U.S. politicians across the spectrum for failing to communicate the goals of the air campaign, told Americans that the military mission in Libya was clear, focused and limited.
He said it had already saved countless civilian lives.
Obama said Libya's air defenses had been disabled, Gaddafi's forces were no longer advancing and, in places such as Benghazi, his forces had been pushed back.
"So make no mistake, because we acted quickly, a humanitarian catastrophe has been avoided and the lives of countless civilians -- innocent men, women and children -- have been saved," Obama said in a weekly radio address.
Obama, due to speak to Americans about Libya again on Monday evening, had also been faulted by fellow politicians for taking on a third military mission in a Muslim country with the United States embroiled already in wars in Iraq and Afghanistan.
NATO has agreed to take over the role of enforcing the no-fly zone and arms embargo against Libya, but final details have not yet been worked out for the alliance to take over.
(Additional reporting by Alexander Dziadosz, Maria Golovnina, Michael Georgy, Ibon Villelabeitia, Lamine Chikhi, Mariam Karouny and Patricia Zengerle; Writing by Tom Pfeiffer and Ibon Villelabeitia; Editing by Louise Ireland)