Libyan rebels fighting to oust Maummar Gaddafi pressed ahead on Thursday with day two of a NATO-backed offensive after seizing a desert hamlet some 50 kilometres (30 miles) from Tripoli.

At the same time, insurgents said forces from their western coastal enclave of Misrata had pushed to within a short distance of Zlitan, some 60 kilometres (36 miles) further west, with 20 killed on both sides.

Reinforced with French weapons parachuted into the North African country and backed by NATO-led air strikes aimed at destroying Gaddafi's frontline armour, the rebels attacked regime forces in the plains southwest of the capital.

The area targeted by that offensive is seen as strategic as it also features the garrison city of Gharyan, a government stronghold in the Nafusa mountains.

"We waited before launching this assault and finally got the green light from NATO... and the offensive began," a rebel leader in Zintan, a hill town, said on Wednesday.

An AFP correspondent embedded with the rebels said there were intense exchanges of artillery, mortar and cannon fire with government troops dug in around Gualish.

In the conflict, several African mercenaries fighting alongside Gaddafi forces were captured.

NATO listed a series of seven targets where Gaddafi's military equipment had been attacked, including eight armoured vehicles and military refuelling equipment near the eastern oil town of Brega.

An anti-aircraft gun had also been taken out close to Gharyan where earlier this week four tanks were destroyed. Eight armed vehicles were also hit in the latest attacks in the vicinity of Zlitan.

In the rebel stronghold of Benghazi, an official statement said "ten of our martyrs were killed and 59 others wounded" on Wednesday in clashes with Gaddafi loyalists in the push on Zlitan.

Ten Gaddafi fighters were also killed, the statement added, saying others had fled. In the process, they abandoned a school used as a weapons depot, and an "enormous amount" of munitions, heavy weapons and military vehicles was captured.

Away from the battle front, tens of thousands of rebel supporters in Benghazi on Wednesday took to the streets in a propaganda riposte to a pro-Gaddafi demonstration which had been beamed to their area of control last Friday.

That rally was a demonstration that the veteran leader still had vast numbers of supporters in Tripoli, while the Benghazi demonstration was aimed at sapping the morale of the pro-Gaddafi crowds and boosting that of the rebels.

On the political front, a senior Chinese diplomat visited Benghazi and met members of the opposition, Chinese state media reported on Thursday, as Beijing showed itself becoming more deeply engaged in the war-torn nation.

Chen Xiaodong, in charge of North African affairs at the foreign ministry, met officials of the opposition's National Transitional Council (NTC), the official Xinhua news agency said.

Chen called for a quick political solution to the four-month-long conflict and urged the rebels to hold talks with officials loyal to Gaddafi, it said.

Until recently, China had maintained its long-standing policy of non-interference and public neutrality on the conflict, calling repeatedly for a peaceful end to the popular uprising.

But it now appears to be getting more involved. Last month, Beijing recognised Libya's opposition as an "important dialogue partner" after talks in the Chinese capital between foreign minister Yang Jiechi and senior rebel leader Mahmud Jibril.

In addition to the NATO assistance, the West has thrown its diplomatic and financial support behind the NTC, which has been recognised by about 20 countries including Britain, France and the United States.

But alliance member Italy, pressed by the need to cut defence spending, announced on Thursday that it was removing the aircraft carrier Garibaldi, its three fighter jets and 1,000 personnel from the Libyan operation.

The Garibaldi would be replaced by a smaller vessel and by warplanes from military bases, Defence Minister Ignazio La Russa said.

And global cultural watchdog Heritage Without Borders warned that Gaddafi may have hidden weapons in the Roman ruins of Leptis Magna, a few kilometres (miles) west of Zlitan, expressing fears that fighting might damage the UN-protected World Heritage Site.