A meeting in Qatar that took place between a Chinese diplomat and the leader of the rebel National Transitional Council follows a spate of defections by high-profile figures this week, including senior oil official and former prime minister Shokri Ghanem.
Libyan rebels and NATO have made Gaddafi's departure a condition for agreeing a ceasefire in the conflict but he emphatically told visiting South African President Jacob Zuma this week he would not leave Libya.
A NATO-led military alliance extended its mission to protect civilians in Libya for a further 90 days this week, and France said it was stepping up military pressure as well as working with those close to Gaddafi to try to persuade him to quit.
"He is more and more isolated," French Foreign Minister Alain Juppe told Europe 1 radio. "There have been more defections around him and we have received messages from his close entourage which has understood that he must leave power."
In Beijing, a terse Chinese Foreign Ministry statement said Beijing's ambassador to Qatar, Zhang Zhiliang, had met and "exchanged views on developments in Libya" with Mustafa Abdel Jalil, the chairman of the rebel council that is trying to offer itself as a credible temporary alterative to Gaddafi.
The ministry gave no details of the talks but the meeting itself was an indication that Beijing wants to keep open lines of communication with the rebel forces.
In Tripoli, government spokesman Moussa Ibrahim said he had no immediate comment on China's meeting with the rebels.
Now in its fourth month, the Libyan conflict is deadlocked, with rebels unable to break out of their strongholds and advance towards Tripoli, where Gaddafi appears to be entrenched.
Rebels control the east of Libya around Benghazi, where the rebel council is based, and a mountain range stretching from the town of Zintan, 150 km (95 miles) south of Tripoli, towards the western border with Tunisia.
In London, Major General John Lorimer said British warplanes destroyed two tanks and two armoured personnel carriers on Thursday in Yafran, 100 km (60 miles) southwest of Tripoli, where he said Gaddafi's forces were continuing to attack rebels.
A rebel spokesman in the Western Mountains town of Nalut, Kalefa Ali, said rebels had been fighting forces loyal to Gaddafi in Trumeet to the south of Yafran and in Bir Ayyad.
The rebels took over Bir Ayyad, a road junction which controls access to Yafran from the north, and replaced the green Libyan flags there with the red, black and green rebel flag, a Reuters cameraman said.
"Bir Ayyad is under rebel control," a rebel called Mohammed told Reuters by telephone. He said no rebel fighters were wounded in the fighting.
In Misrata, rebel leader Abdelsalam reported fighting in Dafniyah to the west of the city. "It started at 10 am and Gaddafi's forces have been shelling Dafniyah since then, using mortars and heavier rockets," he said.
He said revolutionaries in Zlitan had been supplied with weapons and telecommunications equipment from Misrata and Benghazi, and had been waging attacks at night, "but not on the scale that threatens Gaddafi's forces' iron grip on Zlitan".
Zlitan is the next town to the west of Misrata, and one of only three between there and Tripoli. A rebel spokesman there, Mabrouk, said security in the town was tight.
"The brigades have a heavy presence," he said. "They are going around with a special scanner that tracks satellite phones. They know revolutionaries use those. Today they also blocked the main road to Tripoli."
In Tunisia, a U.N. official said the bodies of 150 African refugees fleeing turmoil in Libya had been recovered off the Tunisian coast after the vessels carrying them illegally to Europe got into difficulty.
Tunisian authorities rescued 570 people, but many others went into the water when a stampede to get off the small fishing boats -- combined with the effect of rough seas -- capsized some of the vessels, a Tunisian official said. In all about 250 people were reported on Thursday as missing from the vessels.
The United Nations has said government-held parts of Libya were running out of food and the capital Tripoli this week saw the first big protest in months against Gaddafi's 41-year rule.
Gaddafi says the rebels are armed criminals and al Qaeda militants, and has called the NATO intervention an act of colonial aggression designed to grab Libya's plentiful oil.
Western governments say they believe they are wearing down Gaddafi's ability to control Libya through a combination of diplomatic pressure and military action, although the U.S. role in the conflict in particular has been controversial at home.
The House of Representatives prepared to vote on differing approaches to U.S. involvement in Libya, one directing President Barack Obama to pull U.S. forces out of NATO operations and a second that demands more information about U.S. strategy.
The resolutions are a response from U.S. lawmakers in both main parties who are unhappy the United States is now in a third conflict after Iraq and Afghanistan.