|Government forces have struggled to capture Sirte, the biggest of the towns still in the hands of Gaddafi loyalists [EPA]
Commanders with the National Transitional Council (NTC) said their forces now controlled all three main towns in the Al-Jufra oasis, 24 hours after they announced the capture of Libya's largest desert city, Sabha, in the deep south.
"Al-Jufra - Hun, Waddan and Sokna - is liberated," a military spokesman in Libya's third-largest city Misrata said in a statement early on Thursday.
The defeat of Muammar Gaddafi loyalists in the Saharan oases left his remaining forces in his hometown of Sirte on the Mediterranean coast and the desert city of Bani Walid to its west effectively cut off from any line of escape to the south.
Several key Gaddafi supporters have fled to Niger from Sabha, an NTC spokesman said on Thursday.
NTC leaders said they were holding back from advancing on Gaddafi's last redoubts despite their capture of two key southern oases.
Also on Thursday, Lieutenant General Charles Bouchard, the commander of NATO's Libya air campaign, told the AFP news agency he was confident the NATO mission could be completed "well within" three months after the alliance extended it for another 90 days.
In its operational update on Thursday, NATO said that its warplanes had hit four anti-aircraft guns and a vehicle storage depot around Hun.
The alliance said it had also struck a command and control node and five surface-to-air missile systems in and around Sirte.
NATO's operations commander said resistance among Kadhafi loyalists was now restricted to "only three isolated pockets", referring to Sirte, Bani Walid and Al-Fugaha in the Al-Jufra region.
Bouchard added that Gaddafi forces "are no longer able to conduct coordinated operations throughout Libya", while the number of people at risk from pro-Gaddafi military action had fallen to about 200,000.
He said he had no idea where Gaddafi was, but stressed that the fugitive strongman continues to "give orders" and "entice regime forces" to act.
Tunisia, meanwhile, on Thursday sentenced Baghdadi al-Mahmudi, Libya's former prime minister, to six months in prison for illegal entry.
Al-Mahmudi was arrested overnight in the southern town of Tameghza, near Tunisia's border with Algeria, according to ministry spokesman Hichem Meddeb.
Meddeb said Thursday two others were detained along with al-Mahmoudi after Tunisian officials found none had visas.
"[He] appeared before the state prosecutor in Tozeur [430km Tunis] and was sentenced to six months in prison with immediate effect," Kadhem Zine el Abidine said.
An NTC official said the manhunt for Gaddafi, in hiding for weeks though he occasionally issues defiant audio messages, was drawing closer to its target.
"There is no whole tribe or city on Gaddafi's side," Bani said.
"I'm asking everyone in the south who has any news about the tyrant or his loyalists ... to notify the legal bodies about them."
Battle of Sirte
Elsewhere in Libya, NTC forces have struggled to capture Sirte, the biggest of the towns still outside their control.
Gaddafi's spokesman told the Reuters news agency on Thursday that NATO air raids and interim government forces' shelling of Sirte were killing civilians.
"Between yesterday and this morning, 151 civilians were killed inside their homes as the Grad rockets and other explosives fell upon their heads," Moussa Ibrahim said from an undisclosed location.
His claims could not immediately be verified as journalists were unable to reach the city. NATO comment was also not immediately available.
One fighter said Gaddafi artillery batteries appeared to have found the range of the NTC tanks, and were targeting them.
"There has been heavy shelling from Gaddafi forces," said Adel al-Tarhouni, an anti-Gaddafi fighter in the village of Sultana, which came under artillery attack.
NTC commanders to the west of Sirte said they had been told to expect further NATO air strikes on Thursday and had orders not to advance.
East of Sirte, commanders said that they had postponed any offensive against the city for at least a week for want of ammunition after heavy fighting.
"Fighting has been stopped for a week. We are facing a shortage of ammunition," said Commander Mustafa bin Dardef of the Zintan Brigade, whose troops are some 25km east of Sirte.