Buoyed by French arms drops and intensified NATO air strikes on the regime's frontline armour, Libya's rebel army said it is poised for an offensive that could put it within striking distance of Tripoli.

The rebels' announcement late on Saturday came as a prolonged deadlock on the battlefield prompted mounting pressure from countries outside the NATO-led coalition for a negotiated solution to a conflict that has dragged on for four and a half months.

South Africa, which has taken a lead role in mediation efforts, said that President Jacob Zuma would hold talks in Moscow on Sunday with representatives of the International Contact Group on Libya as well as Russian officials.

Rebel fighters are readying an advance out of their hilltop enclave in the Nafusa Mountains, southwest of Tripoli, in the next 48 hours in a bid to recapture territory in the plains on the road to the capital, spokesman Colonel Ahmed Omar Bani said.

"In the next two days the (revolutionaries) will come up with answers, things will change on the front line," he said.

The rebels had pulled back last week from around the plains town of Bir al-Ghanam, some 80 kilometres (50 miles) from Tripoli, in the face of loyalist bombardment.

But last week France made a series of controversial weapons drops to rebel fighters in the Nafusa Mountains and NATO has bombarded loyalist positions around Bir al-Ghanam and elsewhere on the front line around the rebel enclave.

Two armoured vehicles belonging to Kadhafi forces were destroyed in the town on Friday night.

In Gharyan, another government stronghold near the mountains, NATO aircraft struck eight targets over the past four days, including a military complex used to resupply Kadhafi troops, tanks and other military vehicles, the alliance said on Saturday.

In its daily report for Friday, NATO said it had launched a total of 42 strike sorties over Libya, hitting two tanks near Gharyan and two armed vehicles near Bir al-Ghanam.

Libyan leader Moamer Kadhafi reacted furiously to the French arms drops to the rebels, calling on his supporters Friday to go and retrieve the weapons.

"March on the jebel (mountains) and seize the weapons that the French have supplied," he said.

French Foreign Minister Alain Juppe insisted that the arms were meant only to defend peaceful civilians from Kadhafi's forces and thus fell in line with UN Security Council resolutions on the conflict.

"It is not a violation of the UN Security Council resolutions" under which France and other allies launched air strikes and imposed embargoes to protect civilians from Kadhafi, he said.

There was no immediate confirmation from Moscow of the talks between Russian and South African officials and representatives of the NATO-led coalition but both countries have been outspoken advocates of a negotiated solution to the conflict.

"President Jacob G. Zuma will undertake a working visit to the Russian Federation to participate in the meeting of the International Contact Group on Libya to be held on Sunday, July 3, 2011," the South African foreign ministry said, adding that the visit was at Moscow's invitation.

Ministry spokesman Clayson Monyela said the talks in Russia would include all members of the contact group, but could provide no further details.

The Kremlin said in a statement late Saturday that Zuma and President Dmitry Medvedev held a telephone conversation in which they agreed on a "personal meeting in the closest time" but gave no details on when it would take place.

The announcement by Pretoria came shortly after Zuma returned home from an African Union summit in Equatorial Guinea, where the continental grouping adopted a plan for negotiations between the warring Libyan parties.

"We are very happy that we have reached this point, that we can now say very soon we will be launching the talks in Addis Ababa and we believe we will get the necessary support from everyone," Zuma said after the summit.

But the accord reached in Equatorial Guinea produced little movement on earlier AU proposals, which have been rejected by the rebels who insist that Kadhafi must step down before they will agree to a truce.

New elements in the AU plan include provisions for a multinational peacekeeping force organised by the United Nations.

The bloc also says that Kadhafi has agreed to stay out of the negotiations.