Libyan leader Muammar Gaddafi on Monday called upon his supporters to gear up for a campaign to liberate rebel-held towns, Xinhua news agency reports.

"Advance, challenge, pick up your weapons, and go to the fight to liberate Libya inch by inch from the traitors and NATO," the embattled colonel said in an audio message aired in the early morning by Libyan television.

"Get ready to fight... The blood of martyrs is fuel for the battlefield," Gaddafi said in the appeal, which the broadcaster said was a live speech.

Due to what the TV station called technical problems, the sound quality of the address was poor, and much of the message was inaudible.

In an excerpt of the TV speech published by the JANA news agency, Gaddafi said that the end of the "rats" and "colonizers" is close, referring to the rebels and NATO forces.

Gaddafi made the call amid rumors that he was about to go into exile. The Libyan leader, who ruled the North African country for 41 years, has vowed never to leave his homeland.

The message also came as rebel forces fighting to topple him had apparently broken the recent stalemate on the battleground and further closed in on the capital.

The rebels said Sunday that they had defeated pro-Gaddafi troops in Zawiyah and captured the strategic town just 40 km west of Tripoli. The Libyan government, however, has denied the claim.

Zawiyah is of great strategic importance, as it sits on the main highway linking the capital with Tunisia, which serves as an important lifeline for the Libyan government.

Libya has been embroiled for months in the deadliest of a spate of turbulence sweeping West Asia and North Africa. Some Western and Arab powers militarily intervened in March under the name of a UN resolution adopted to protect Libyan civilians, and NATO took over control of the mission weeks later.