Aid workers from the International Committee of the Red Cross (ICRC) brought medical supplies into Muammar Gaddafi's besieged hometown of Sirte on Saturday as fears grew that a humanitarian disaster may unfold inside.

Civilians have been streaming out of Sirte in their hundreds over the last few days as interim government forces intensified their shelling of the coastal city in an effort to dislodge fighters loyal to Gaddafi.

The prolonged battle for Sirte, encircled by anti-Gaddafi fighters and hit by regular Nato airstrikes, has trapped people inside the town of about 100,000 people through several fierce assaults over two weeks.

Fighting continued on fronts to the west and east of the town on Saturday, with both sides again exchanging rocket and mortar fire. Loud thuds were heard from the centre, and white smoke billowed up into skies where Nato planes roared.

A truckload of supplies and two cars carrying European ICRC workers arrived at western checkpoint manned by fighters loyal to the ruling National Transitional Council (NTC).

Some NTC commanders said they would try to allow the foreign workers safe passage into the city but shelling continued.

An ICRC worker, Karen Strugg, told Reuters her colleagues had made it inside.

'They're inside delivering medical aid. And they want to come out,' Strugg said on a road leading into the centre.

Fighting remained heavy at a roundabout in the east of the city where NTC fighters have been held at bay for six days by artillery and sniper fire from pro-Gaddafi forces.

NTC commanders said the snipers were the main factor frustrating their advance. Reuters journalists have seen some anti-Gaddafi fighters run from the front under the fire.

On Saturday, when a truck careened back from the roundabout carrying a dead NTC fighter, his comrades fired into the air and began to shout, 'Muammar, the rat! He is killing us!'

Gaddafi loyalists and some civilians were blaming Nato air strikes and shelling by NTC forces for killing civilians.

Nato and the NTC deny that. They and some other civilians coming out of the town say pro-Gaddafi fighters are executing people they believe to be NTC sympathisers.

The NTC is under pressure to strike a balance between a prolonged fight that would delay its efforts to govern and a quick victory which, if too bloody, could worsen divisions and embarrass the fledgling government and its foreign backers.

"This war is going to go for a long time. Do you know why? It's because of the snipers. What will finish it is the rockets but they can't do that because of the civilians," a man called Mohammed said as he fled with his parents.

NTC officials have been shocked by the intensity of the resistance from the pro-Gaddafi fighters at Sirte and Bani Walid, the other main town holding out.

On Friday evening, one person was killed and six were wounded when pro-Gaddafi fighters emerged from Bani Walid and staged a surprise attack on the eastern flank of NTC forces stationed to the north, residents of the area told Reuters on Saturday.

The residents said it was believed to be the third or fourth time that such an assault had been attempted by the town's defenders since the start of the NTC's attack in early September.

As concern mounts for people in both towns, several residents have told Reuters they are leaving Sirte because they have not eaten for days.

"I am not scared. I am hungry," said Ghazi Abdul-Wahab, a Syrian who has lived in the town for 40 years.

Some residents say they had paid up to $800 for fuel to leave the city because it was scarce. Others said pasta and flour were now changing hands for large sums of money.

Doctors at a field hospital said an elderly woman died from malnutrition and they had seen other cases.-Reuters