The opposition advances mark small progress in a largely deadlocked civil war. Fighting began nearly five months ago when a popular uprising against Qaddafi quickly escalated into armed conflict.
NATO said Wednesday that its warplanes have destroyed 2,700 military targets, including 600 Libyan tanks and artillery guns and nearly 800 ammunition stores, since the alliance began bombing Qaddafi-linked sites in March, under a UN mandate to protect Libyan civilians.
Secretary-General Anders Fogh Rasmussen warned that Qaddafi's forces remain a threat. "Without NATO there would be a massacre. Qaddafi would be free to use his tanks and missiles on towns and markets," he said. "We will not let that happen."
NATO's campaign was intended to deliver a sharp, devastating blow. However, with the campaign dragging on inconclusively, there have been increasing international calls for a negotiated end to the war. The ragtag opposition forces to the east and south of Qaddafi's stronghold in the capital Tripoli have failed to achieve a breakthrough in recent months.
Still, fighters in the Nafusa mountains southwest of Tripoli seized control Wednesday of two towns after pushing out government forces, a member of the local military council said.
Col. Gomaa Ibrahim said via Skype that opposition forces moved into Qawalish and Kikla on Wednesday morning, after a battle in which one fighter was killed and five were injured. It was unclear if any government soldiers were killed.
While the two towns are small, their capture further expands the area seized from government troops in recent months by relatively small bands of mountain fighters. A string of similar victories has left the opposition in control of most of the Nafusa mountains, bringing them within about 160 kilometers of Tripoli.
Most of Libya's opposition-held territory lies in the east, where the National Transitional Council (NTC) runs the movement from its de facto capital in Benghazi.
NATO airstrikes, regime defections and increasing international isolation have eroded Qaddafi's grip on the country. His regime struck back Wednesday, saying it planned to charge opposition leaders with treason. A judge compiling the charges laid out his case against 21 opposition officials, including the NTC's head, Mustafa Abdul-Jalil. Defendants will be tried in absentia.
Prosecutors at the Netherlands-based International Criminal Court have alleged that those who gave orders to government troops to fire on civilian protesters during anti-Qaddafi demonstrations could be tried for war crimes.
Libyan officials reject the ICC's authority, saying their special court will bring justice to anyone who committed crimes during the uprising. "We are ready and prepared to investigate any person in this country if there are people who are willing to come to the (attorney general) with accusations or complaints," a government spokesman said.
