A popular uprising against the strongman that began in mid-February has left the oil-rich North African state split between the largely Kadhafi-controlled west and the rebel east.
Libya's foreign ministry meanwhile said Monday's visit by German Foreign Minister Guido Westerwelle to Benghazi, the rebels' de facto capital, was a "flagrant violation" of Tripoli's sovereignty.
It condemned the trip as "irresponsible" and said it "does not help efforts by regional and international organisations to find a peaceful solution to what is happening in Libya."
During his visit to Benghazi, Westerwelle said Kadhafi "had lost all legitimacy" and announced Berlin's recognition of the NTC as the "legitimate representative" of the Libyan people.
Liberia on Tuesday broke diplomatic ties with Libya one day after US Secretary of State Hillary Clinton pressed all African states to demand Kadhafi step down and take tougher action against his regime.
Senegal and Gambia are the only African states to have recognised the NTC as the legitimate interlocutor.
South African President Jacob Zuma on Tuesday said NATO's air campaign abused a UN resolution to protect Libyan civilians for regime change and "political assassinations".
"We strongly believe that the resolution is being abused for regime change, political assassinations and foreign military occupation," Zuma said in a speech to parliament.
He added NATO's actions undermined African Union efforts to find a solution.
The rebels succeeded in driving out pro-Kadhafi forces and seizing Al-Rayaniya, a village east of the heavily fought-over hilltown of Zintan, in the mainly Berber Nafusa mountains, southwest of Tripoli, an AFP correspondent reported.
The village of some 10,000 residents falls on a strategic route connecting Zintan and Yefren, two towns rebels hope to wrest from forces loyal to Moamer Kadhafi.
Pro-Kadhafi forces, however, continue to bomb the town with Grad rockets.
Shells and rockets fired during combat breached the border with Tunisia on Tuesday, witnesses told AFP, one reporting a large Tunisian military presence on the frontier.
In the east, the frontline between the rebel-held transport hub of Ajdabiya and the strategic oil town of Brega was calm on Tuesday, rebel commander Mussa al Mograbi told AFP by telephone.
"There was no fighting today against Kadhafi's forces. The day was calm," said Mograbi, who reported four of his men were killed and 30 wounded in a skirmish the previous day.
NATO on Tuesday said it "has the resources" to conduct its campaign in Libya despite a warning from Washington that reliance on US military could jeopardise the mission.
"We continue to maintain a high tempo of operation," said NATO spokeswoman Oana Lungescu. "It is clear that NATO has the resources to keep up the pressure on the (Moamer) Kadhafi regime. We know it takes time."
But in Belgrade, one of NATO's top commanders warned that the issue of resources "will become critical" if the conflict dragged on.
"If the operation was to last longer, of course the resource issue will become critical," Supreme Allied Commander of Transformations, French General Stephane Abrial said.
Last week, US Defence Secretary Robert Gates issued a stinging rebuke to NATO allies as only eight of the 28 members are conducting air strikes against Kadhafi's regime.