Sirte: Ferocious attacks by Gaddafi diehards forced fighters of Libya's new rulers to retreat from the ousted strongman's birthplace Sirte, where a tank shell killed three in a "friendly fire" attack.

Equally fierce resistance from loyalists in the desert town of Bani Walid, Muammar Gaddafi's other remaining bastion of support, has stalled a final assault by National Transitional Council (NTC) fighters, said commanders, who called on Nat to increase its air support.

While the fugitive Gaddafi's whereabouts remain unknown, Libya's defence ministry spokesman Ahmad Bani said in Tripoli one of his sons, Saif Al Islam, was in Bani Walid and another, Mutassim, in Sirte.

Along with his father and former intelligence chief Abdullah Al Senussi, Saif is wanted by the International Criminal Court for alleged crimes against humanity.

An NTC commander in eastern Sirte told AFP that fighting which raged into Wednesday night was the fiercest yet since new regime forces launched their assault on the Mediterranean port city on September 15.

"There were heavy clashes (on Wednesday). Our men came under heavy attack," said the commander, who asked not to be identified.

The fighting was so intense, he added, that his forces were forced to retreat three kilometres outside the city.

"They (Gaddafi loyalists) have lost everything. This is their last battle and so are fighting fiercely. Our troops are taking a heavy beating at the moment. Today we retreated three kilometres," he said, adding that battles were concentrated at the port and the city's eastern outskirts.

NTC fighters captured the port in east Sirte two days ago, in a major victory for their battle for control of the Gaddafi stronghold.

It was unclear whether the port was still under their control, but the commander said NTC forces were still present there late on Wednesday.
"It is becoming a day-to-day fight. One day we are winning, the next day they are winning," he said.

In a separate incident, three NTC fighters were killed by "friendly fire" on Wednesday when they were shelled by a tank on the frontline in eastern Sirte, the commander said.

"There was some lack of coordination and... our fighters were hit by a shell fired by our tank stationed behind them. There were three martyrs," he said.
In another incident, medics at a field hospital about 50 kilometres west of Sirte said on Thursday two fighters were killed and 18 were wounded when a rocket in a munitions dump fired accidentally, possibly due to rain, and slammed into their room.

The anti-Gaddafi forces have urged NATO to intensify its air war because of heavy losses both in Sirte and in Bani Walid, where senior NTC commander Daou Al Salhine Al Jadak was among 11 fighters killed in a rocket barrage on Tuesday.