Nearly 12 hours of allied air strikes have broken the Libyan regime's five-day bloody assault on the key rebel-held town of Misrata.

Residents said the aerial bombardment destroyed tanks and artillery and sent many of Muammar Gaddafi's forces fleeing from Misrata, ending a siege and attack by the regime that cost nearly 100 lives from random shelling, snipers and bitter street fighting.

Mohammed Ali, an IT engineer at Misrata's main hospital, said that waves of air strikes began shortly after midnight on Wednesday.

"They bombed a lot of sites of the Gaddafi army. There is a former hospital where his tanks were based. All the tanks and the hospital were destroyed. A column of tanks was destroyed on the edge of the city," he said. "After that there was no shelling. We are very relieved. We are very grateful. We want to thank the world. The Gaddafi forces are scattered around. All that is left is the snipers and our fighters can take care of them."

Ali said people in Misrata wanted the coalition to keep up the air strikes until all Gaddafi's forces were driven away from the town to ensure that those who were able to escape with armoured vehicles and guns did not return.

A doctor in the town, who did not want to be named, said snipers were continuing to sow fear by targeting not only rebels but civilians.

"The sniper problem is a big one. A lot of people are still afraid to leave their homes," he said.

The apparent breaking of the siege will be a blow to the Libyan ruler's attempts to reassert control over the entire west of the country.

It may also serve as a further deterrent, along with the destruction of Gaddafi's tanks, artillery and soldiers that were attacking Benghazi, to those still fighting for the dictator.

But it did not stop the regime's forces from continuing to put up stiff resistance around the strategic town of Ajdabiya in the east, despite repeated coalition bombing raids.

Ali described the past five days of attack on Misrata as "hell".

"It was crazy in the last five days. The hospital was overwhelmed. Ninety four people were killed. Sixty of them were civilians. Whole families were wiped out driving in their cars," he said. "The injured were more than 1,300. About 115 serious cases were kept in hospital. Everyone without life threatening injures was sent home. I've seen people who've just had a leg amputated sent home."

Ali said that the town has had no water or electricity for nine days. The medical centre is running on a generator.

The air strikes in and around Misrata suggest that what appears to be a tactic of Gaddafi's forces to shelter in residential areas, in response to the destruction of tanks and guns on the open desert road near Benghazi, has not provided protection. Residents of the town said that the coalition aircraft managed to destroy the regime's armour without any known civilian casualties.

The revolutionary leadership has said that even if there are civilian casualties, they will be a necessary price to prevent even greater loss of life if Gaddafi's forces had continued their assault on Misrata and exacted revenge against the residents for their support of the uprising.

The US military said that its intelligence showed Gaddafi's forces remained a threat to Misrata as well as remaining entrenched around Ajdabiya, where the regime's fighters have put up sustained resistance for three days despite several air attacks by coalition planes.

Rear Admiral Gerard Hueber, chief of staff of operation Odyssey Dawn, said the coalition would continue its attacks on Gaddafi's ground forces in both places as well as other cities under assault by the regime. Hueber said the air attacks were aimed at preventing the regime's army from entering rebel-held cities as well as cutting supply and communication lines. But he admitted that Gaddafi's forces were making incursions into some cities and targeting civilians.

People fleeing Ajdabiya said that civilians continued to be killed in the town even though most of the residents have left.

Hamad Abdul Rahim drove along a desert track with his mother, wife and children, including two young daughters, crammed into a car to escape the town on Wednesday.

"There was a lot of shelling last night. There are hundreds of Gaddafi men there. Many of them are not from Libya. They are African people. We saw them," he said. "Many people have died. Some were shot on the street by Gaddafi's men."

The regime's army continued to keep the rebels at bay just outside the town with periodic shelling of the revolutionaries' front line, some of it intense. An ambulance driver described carrying away two dead rebels who were on the back of a pick-up truck with a mounted machine gun when they took a direct hit from a shell.

The rebels say they are waiting for allied air strikes to destroy the tanks and artillery Gaddafi has around Ajdabiya before they attempt to take the town.

Gaddafi's forces also kept up their bombardment of Zintan in the west.

"The town is completely surrounded. The situation is very bad," the resident, Abdulrahman, told Reuters by telephone from the town. "They are getting reinforcements. Troops backed with tanks and vehicles are coming. We appeal to the allied forces to come and protect civilians."

Hueber found himself in difficulty when questioned about whether the US was co-ordinating its attacks with rebel forces, which might be in breach of the UN mandate.

Initially, he confirmed that US forces were consulting the rebels about their movements but later in the press conference he backtracked, saying: "I mis-stated that".

He said that the US had communication lines to the Gaddafi regime warning them to pull back their forces.

British aircraft flew over Libya yesterday, but for the second day running took no part in attacks, according to defence officials.

The commander of British aircraft operating over Libya has said that Colonel Gaddafi's air force "no longer exists as a fighting force".

Air Vice-Marshal Greg Bagwell said the allies could now operate "with near impunity" over the skies of Libya.