Col Gaddafi's whereabouts are unknown, though rebels have said they think he is still in or around Tripoli.

Rebel’s fighters have fought running battles in the capital, where pockets of pro-Gaddafi resistance remain.

The fugitive leader has vowed in an audio message to fight until victory or martyrdom.

His sprawling Bab al-Aziziya compound was overrun on August 23, though firefights within the complex have continued.

Col Gaddafi's forces are still firmly in control of his birthplace - the strategic coastal city of Sirte - as well as several key bases in southern Libya.

The head of the National Transitional Council (NTC), Mustafa Abdel Jalil, announced the amnesty offer from the eastern city of Benghazi.

"Gaddafi's forces and his accomplices will not stop resisting until Gaddafi is caught or killed," he said.

He added that the NTC supported an offer by a group of businessmen to pay US$1.7m for Col Gaddafi, "dead or alive".

The rebel leadership has also offered Col Gaddafi safe passage out of the country, if he renounces his leadership.