Libya's deposed leader Muammar Gaddafi has said the system of rule he set up was based on the people's will and could not be removed.
Speaking in a recorded message broadcast by Syrian-based Arrai television, he also said NATO's planes would not be able to continue their operations in Libya.
"The political system in Libya is a system based on the power of the people ... and it is impossible that this system be removed," he said. "The bombs of NATO planes will not last."
Anti-Gaddafi fighters today claimed to have captured the airport and a garrison in the defeated former Libyan ruler's southern stronghold of Sabha, as fighting raged in two of his northern strongholds.
The battlefield victories came as the US and its allies prepared to meet on the sidelines of the UN General Assembly in New York to discuss the future of the new Libya.
National Transitional Council forces earlier announced the capture of the key locations in Sabha, a strategic desert city 800km south of Tripoli.
Fighting still raged in some quarters, but the pro-NTC forces would take total control of Sabha "in some hours," said Mohammed Wardugu, spokesman for the "Desert Shield Brigade".
They also had seized one of Gaddafi's senior generals and forced more than 300 of his mercenaries to flee, said Mr Wardugu, brother of brigade commander Barka Wardugu.
"General Belgacem Al-Abaaj, Gaddafi's intelligence chief in the Al-Khofra region, was captured" yesterday some 100km from Sabha, said Wardugu.
Gen Abaaj, who had been sought by the forces of the NTC, was seized with members of his family who were travelling in five four-wheel drive vehicles.
In the north, dozens of new regime fighters stormed the town of Sultana, braving rocket and artillery attacks as they marked another victory in their march towards Sirte, the fugitive Gaddafi's hometown on the Mediterranean coast.
The column of fighters advancing on Sirte from the west were to join other NTC forces already at the gates of the city who have been fighting Gaddafi loyalists there since the weekend.
Fighting had also raged yesterday in Bani Walid when NTC fighters attacked the oasis town southeast of Tripoli where Gaddafi's son Saif al-Islam is believed holed up, possibly with his father.
Gaddafi, Saif al-Islam and intelligence chief Abdullah al-Senussi have been on the run since rebels overran Tripoli on 23 August.
They are wanted by the International Criminal Court for alleged crimes against humanity.
Libya's NTC attend UN assembly
US President Barack Obama has called for the last of Gaddafi's forces to lay down their arms.
Mr Obama was speaking after he met chairman of the Transitional National Council Mustafa Abdul Jalil in New York.
The meeting came before high-level UN conference on the future of Libya.
Mr Obama announced the return of the US ambassador to Tripoli and pledged to help Libya rebuild.
"Today, the Libyan people are writing a new chapter in the life of their nation," Mr Obama said.
"We will stand with you in your struggle to realise the peace and prosperity that freedom can bring.
"Those still holding out must understand-the old regime is over, and it is time to lay down your arms and join the new Libya."
Elsewhere, the African Union has officially recognised the NTC as Libya's legitimate leadership.
