Evacuees of the rebel-held city of Misrata have spoken of the desperate situation in the city, which is under fresh attacks from forces loyal to defiant Libyan leader Moamar Gaddafi.

Misrata is the only big rebel stronghold left in western Libya and has been under attack for weeks.

Rebels say the most recent shelling is targeting residential areas.

A rebel spokesman said the city was shelled on Monday.

"The shelling started in the early hours of the morning and it's continuing, using mortars and artillery. This is pure terrorism. The shelling is targeting residential areas," a rebel spokesman called Gemal said.

Accounts from Misrata cannot be independently verified because Libyan authorities are not allowing journalists to report freely from the city.

An aid ship operated by charity Medecins Sans Frontieres docked in the Tunisian port of Sfax carrying 71 injured people from Misrata, many with bullet wounds and broken limbs and one whose face was completely disfigured by burns.

One of the Misrata residents who has escaped to Tunisia says bodies lie in the streets of the besieged city and its hospital is overflowing with injured.

"You have to visit Misrata to see the massacre by Gaddafi," said Omar Boubaker, a 40-year-old engineer who was shot in the leg.

"Corpses in the street... the hospital overflowing. Doctors taking care of people in the street. There's no space left in the hospital."

The port of Sfax echoed to the sound of sirens as a stream of ambulances ferried the wounded to hospital.

Abdullah Lacheeb, who has serious injuries to his pelvis and stomach and a bullet wound in his leg, cried as he said: "Look what Gaddafi and his sons have done, just because we protested peacefully."

"I could live or die but I am thinking of my family and friends who are stranded in the hell of Misrata."

"Imagine, they use tanks against civilians. He is prepared to kill everyone there."

Libyan officials deny attacking civilians in Misrata, saying that they are fighting armed gangs linked to Al Qaeda.

Another injured man, called Imed, says Misrata needs outside help to withstand the attacks.

"We cannot do anything against this massacre any more. We ask the Americans and the Europeans to put people on the ground and help us end these crimes," he said.

"We need you on the ground to protect us."

Western aircraft have targeted government forces in the city with air strikes but have so far been unable to halt the attacks by pro-Gaddafi units, who residents say have stationed snipers on rooftops and are firing mortars and artillery at houses.

The Misrata attacks come as Libyan rebels advancing towards the oil town of Brega, in renewed fighting in eastern Libya.

Rebels have pushed towards Brega in an attempt to win back territory lost pro-Gaddafi forces.

A BBC correspondent near Brega says the rebels are clearly bolstered by the presence in their ranks of more and more soldiers who have defected from Mr Gaddafi's army.

Diplomatic offensive

Meanwhile, there were signs on Monday that Mr Gaddafi's regime may be looking for a diplomatic way out of the bloody stalemate.

Libyan deputy foreign minister Abdel-ati Obeidi flew to Athens on the weekend carrying a personal message from Mr Gaddafi to prime minister George Papandreou that Libya wanted the fighting to end.

"The Libyan envoy wanted to convey that Libya has the intention to negotiate," a Greek official said after the visit.

Greek foreign minister Dimitris Droutsas says the envoy is now set to travel to Turkey and then on to Malta in a diplomatic offensive.

But Italian foreign minister Franco Frattini, who had spoken to Greek officials, dismissed the Libyan envoy's message, saying a divided Libya was not acceptable and Mr Gaddafi must quit.

After a meeting with Ali Essawi, a member of the Libyan rebel council looking after foreign affairs, Mr Frattini said Italy, the former colonial power in Libya, backed the rebels.

"We have decided to recognise the council as the only political, legitimate interlocutor to represent Libya," he said.

"A solution for the future of Libya has a pre-condition - that Gaddafi's regime leaves and is out and that Gaddafi himself and his family leave the country," he said, adding an interim government headed by one of Mr Gaddafi's sons was "not an option".

Mr Gaddafi believes the uprising is fuelled by Islamist radicals and Western nations who want to control Libya's oil.

The rebels, whose stronghold is in the eastern city of Benghazi, want nothing less than the removal of Mr Gaddafi and his circle.

The UN-mandated military intervention, in which warplanes have attacked Mr Gaddafi's armour, radars and air defences, began on March 19 and was intended to protect civilians caught up in fighting between pro-Gaddafi forces and the rebels.

But neither the pro-Gaddafi troops nor the mostly disorganised rebel force have been able to gain the upper hand on the frontline, despite the Western air power in effect aiding the insurgents.

- Reuters