US defence secretary Robert Gates says Libyan troops are placing bodies at the sites of coalition air strikes and then blaming western forces for their deaths.

The accusation comes as France says its fighter aircraft have destroyed at least five Libyan government warplanes and two helicopters near the city of Misrata.

Rebel forces say they have claimed the eastern town of Brega shortly after recapturing Ajdabiya.

The government of embattled leader Moamar Gaddafi says around 100 people have been killed in a week of coalition air strikes on Libya.

"Tonight the air strikes against our nation continue with full power," said government spokesman Moussa Ibrahim.

"We are losing many lives, military and civilians.

"Today the air strikes continued for hours and hours non-stop ... We believe many civilians were killed, including some families who are escaping the air strikes in their cars.

"We think this is murder, this is immoral, this is illegal, this is not the mandate of the Security Council."

But speaking to American network CBS, Mr Gates said the US was having trouble coming up with proof of any civilian casualties caused by the coalition.

He said numerous intelligence reports suggested Mr Gaddafi's forces were collecting the bodies of the people they killed in their assaults and dumping them at the sites of allied strikes.

Asked if Mr Gaddafi's days were numbered, he said "I wouldn't be hanging any new pictures if I were him."

Meanwhile, France says five Libyan government warplanes and two helicopters were destroyed near the city of Misrata as troops were preparing to carry out bombing operations in the region.

Forces loyal to Mr Gaddafi have been attacking opposition rebels in Misrata for weeks, and one resident told the BBC he believes the rebels are struggling under the constant assaults.

"[It] looks like Gaddafi's troops still have the upper hand, and they have unlimited supply of ammunition," he said.

"The rebels and the people here are totally panicked. They have limited ammunition and I don't know how long the city is going to last against this strong and fierce attack."

The rebels are pressing on west after re-capturing the city Ajdabiya from pro-government forces.

Having secured Ajdabiya, they are now chasing the retreating Libyan army down the road to the next town, Brega.

The opposition claims to have captured it already, but there has been no confirmation.

-AFP/BBC