Volunteers are still finding dozens of bodies in Moamer Kadhafi's hometown of Sirte that fell on October 20, including those of Libyan civilians killed in a suspected NATO air strike.

Twenty-six makeshift and unmarked graves covered by breeze-blocks were discovered at a water treatment plant in Number Two district where pro-Kadhafi fighters put up a final stand after several weeks of heavy bombardment.

With the pungent odour of decomposing bodies filling the air, the shallow graves in the sand were scattered amidst the plant's devastated buildings, an AFP correspondent said.

According to Ibrahim Suleiman, one of the volunteers collecting bodies in Sirte over the past week, they were of pro-Kadhafi fighters hastily buried by comrades as new regime forces closed in on the city.

Suleiman said he and his colleagues have buried a total of more than 500 bodies across Sirte since October 23, most of them believed to be fighters. It was unclear if other teams were doing the same work.

"We buried more than 500 bodies since last Sunday, and we keep on finding more throughout the city. Most of them are fighters, I think, but I am not really sure," said Suleiman.

In the centre, at the crossroads of Dubai and September 1 streets, Libyan charity Jabal al-Akhdar told AFP more than 50 bodies of civilians were found under the rubble of a several-storey building flattened in a NATO air strike.

"There are more than 50 civilians under the rubble, of women, of children. It's horrible. We can't get access. It would take bulldozers," said a teary-eyed member of the charity, Mohammed Muftah.

Ayman Ibrahim, another charity member, said "the building collapsed after a NATO air strike."

Local residents backed up the account of an air strike that left behind a huge crater of the type that could not have been left by weapons used by Kadhafi's fighters or their foes in the National Transitional Council.

Another volunteer, Mohammed Yunes al-Hemali, said they are tipped off about corpses by returning local residents. "Often when they return home, the families find a body or a makeshift grave in their property," he said.

The 32-year-old Hemali, a former taxi driver, has been carrying out the macabre task of collecting the bodies for the past five days.

"We drive around, we search, ask people. Sometimes people come to us to tell us they find bodies on their property. Families who return to Sirte often find a body or a makeshift grave on their property," he said.

"We gather them, we clean them and then we give them a decent burial," Hemali added.

Between 65 and 70 bodies were found rotting on the lawn of Al-Mahari hotel, some with their hands bound, many with a bullet in the head.

NTC fighters said they were executed by Kadhafi's forces before the fall of the city, but Human Rights Watch, which carried out an investigation, said they were more likely executed by anti-Kadhafi fighters.

On the outskirts of town, 200 charred bodies were found of pro-Kadhafi fighters hit in NATO air strikes on a convoy when they fled as the eight-month conflict ended with the capture and killing of the ousted strongman.

"I was against these killings from the start, be it from one side or the other, but I was the only one (to think that way)," said Hemali.

"I am sad to see my city in such a state. The thwar (revolutionaries) could have taken it without causing so much destruction. But there was stiff resistance from Kadhafi's men and I think the thwar wanted to punish Sirte because most of the people, even my relatives, supported Kadhafi," he added.