This article is more than 9 years old

This article is more than 9 years old

Forces loyal to Muammar Gaddafi claim to have come under fierce attack as they tried to retreat from the rebel-held city of Misrata.

The Libyan government earlier said Nato air strikes may force it to withdraw from the port city, 120 miles east of Tripoli, and let tribes loyal to Gaddafi deal with rebels.

Early this morning, Nato bombs hit what appeared to be a bunker in Gaddafi's Tripoli compound. Government spokesman Moussa Ibrahim said three people were killed by the "very powerful explosion" in a car park.

Reuters reporters said they saw two large holes in the ground where the bombs had penetrated what appeared to be an underground bunker.

The strike came after the most senior American military officer admitted the conflict was heading towards a "stalemate" despite more than a month of allied strikes against Gaddafi's forces.

Admiral Mike Mullen, chairman of the US military's joint chiefs of staff, said Gaddafi's ground forces had been degraded by 30% to 40%.

But he warned that Nato forces faced a protracted military engagement in the civil war-torn country.

"It's certainly moving towards a stalemate," Mullen told American troops during a visit to Iraq's capital, Baghdad, on Friday. "At the same time, we've attrited somewhere between 30% and 40% of his main ground forces, his ground force capabilities. Those will continue to go away over time."

He said the allies would "put the squeeze" on the Libyan dictator "until he's gone".

"Gaddafi's gotta go," he said.

A group of wounded Libyan soldiers captured by rebels in Misrata, the last large city held by rebels in the west of the country, said they had come under fierce attack from anti-Gaddafi forces as the army tried to retreat.

"We have been told to withdraw. We were told to withdraw yesterday," one soldier, Khaled Dorman, told Reuters.

Ayad Muhammad, another soldier, said: "The rebels attacked us while we were withdrawing from Misrata near a bridge this morning,"

Another serviceman told the news agency the Libyan government had lost control over Misrata, the country's third largest city.

Reuters reported that it was unclear how far out of Misrata the army had managed to withdraw.

Earlier, the Libyan deputy foreign minister, Khaled Kaim, said the army had been given an "ultimatum" to stop the rebellion in Misrata, which has been under siege for nearly two months. Hundreds of people have died in shelling and fighting, petrol is scarce and thousands of migrant workers are trapped there.