Libya's tribes urged Muammar Gaddafi to cede power, as rebels backed by Nato air strikes said they drove the strongman's forces out of missile range of the lifeline port of Misrata.
Rebels defending Zintan, in the mountains southwest of Tripoli, also pushed back Gaddafi forces who bombarded the town with at least 20 Grad rockets, wounding three people and damaging a local hospital, before retreating.
An AFP team in the town late on Wednesday witnessed rebels firing off celebratory salvos into the night as a Nato warplane flew overhead.
Meanwhile, the United States opened another lifeline to the rebels by authorising Americans to buy oil, gas and petroleum products from the rebels' Transitional National Council.
"The people of Libya are brave and defiant but we need access to oil revenues so that we can feed, protect and defend our families," the council said in welcoming the move by the US Treasury Department.
Chiefs or representatives of 61 tribes from across the North African country called for an end to Gaddafi's four-decade rule, in a joint statement released by French writer Bernard-Henri Levy.
"Faced with the threats weighing on the unity of our country, faced with the manoeuvres and propaganda of the dictator and his family, we solemnly declare: Nothing will divide us," said the statement, released on Wednesday in Benghazi.
"We share the same ideal of a free, democratic and united Libya.
"The Libya of tomorrow, once the dictator has gone, will be a united Libya, with Tripoli as its capital and where we will at last be free to build a civil society according to our own wishes," it said.
Levy has become an unofficial spokesperson in Paris for the revolt and is credited with pressing President Nicolas Sarkozy to mobilise international political and military support for it.
"Each of the tribes in Libya is represented by at least a representative. In this list of 61 signatures, some tribes are represented 100-percent, others are still divided," he said.
Gaddafi's forces pushed back
Their call came as rebels said they had managed to push back Gaddafi's forces and secure the besieged port of Misrata, a day after it came under sustained rocket fire.
The insurgents said Nato raids overnight enabled them to force Gaddafi's troops 40-kilometres from the city, which is pressed by regime forces from the east, west and south.
That put Gaddafi's Grad rockets out of range of the port, an aid conduit for rebels in the western city of half a million people under siege for more than seven weeks.
Further west, Gaddafi forces were massed in force in an apparent bid to recapture the Dehiba border post with Tunisia, a Western military source said.
Witnesses said the area was rocked by artillery and mortar fire.
"There is a lot of fire in the area at the foot of the mountains," said a taxi driver at the border, 200-kilometres south of Ras Jdir, the main crossing point into Tunisia that the rebels seized on Thursday.
Security sources in Tunis said Gaddafi fighters tried earlier on Wednesday to enter Tunisia at a point south of Dehiba in a bid to sneak up on the rebels, but were stopped by Tunisian forces.
In Zintan, the two sides exchanged fire with anti-aircraft guns into the afternoon but the insurgents were able to advance on the pro-Gaddafi forces in the surrounding hills until they withdrew to a village held by a friendly tribe.
The mountainous area was one of the first to rise up against Gaddafi's regime in March, but there has been an upsurge in fighting in recent days.
McCain wants to arm rebels
Meanwhile, influential US Senator John McCain said Washington should help arm the rebels, even if the US did not supply weapons directly.
"There is a possibility if not a probability of a stalemate, and that should be of deep concern to us," the former Republican presidential candidate and member of the Senate Armed Services Committee told AFP in Paris.
"The US needs to recognise the TNC (Transitional National Council) as France and Italy have done. They need to get supplies and equipment into the liberation forces and we need to get American air power back into the fight."
McCain said he remains opposed to sending US ground troops to Libya, but confirmed that he supported sending weapons to the rebels.
"I think we could do the same thing that we did in the Afghan struggle against the Russians. There are ways to get weapons in without direct US supplying," he said, referring to US covert action in the 1980s.
'Revenge, revenge, revenge'
Speaking to AFP before the rebels claimed they drove regime forces back from Misrata, the military spokesperson in the rebels' eastern stronghold of Benghazi said Gaddafi was determined to destroy the port.
"This port is too much of a headache for Gaddafi so he wants to destroy it at whatever cost," said Colonel Ahmed Omar Bani, military spokesperson of the Transitional National Council (TNC).
Hitting Gaddafi's troops, he said, remained a challenge even for Nato's forces as loyalists were using civilian areas in the outskirts — schools, shops and farms — to hide troops and weapons.
"It is still hard for Nato to catch them. Gaddafi is staying far from the centre because it is safe for him," he said, warning that losing the port would be a "real disaster," leaving civilians stranded without aid.
He warned that Gaddafi could take "revenge" on the city that rose up against him on 19 February, two days after Benghazi.
"This is the culture of Gaddafi: revenge, revenge, revenge," he said.
Separately, TNC vice chairperson Abdel Hafid Ghoqa said the rebels would free five captured Gaddafi soldiers, turning them over to the International Committee of the Red Cross.
He said the rebels are holding 32 Libyan prisoners alongside 72 foreign mercenaries who are still being questioned and will likely face criminal charges before a justice minister once the conflict is over.
Meanwhile, the African Union urged an end to military actions targeting senior Libyan officials and key infrastructure, after Washington and London had said it was legitimate to strike Gaddafi's compound, as Nato did two days ago.
And Gaddafi's chief ally in Latin America, Venezuelan President Hugo Chavez, accused Nato of trying to kill his "friend."
On Tuesday, US Defence Secretary Robert Gates and British Defence Secretary Liam Fox insisted command centres for the regime's forces were legitimate targets.
Tripoli said late on Tuesday it had asked Russia to convene an urgent meeting of the UN Security Council over what it called an "assassination attempt" on Gaddafi when the Nato raid destroyed his office on Sunday night.
Italy, Libya's former colonial ruler, said on Wednesday it will arm eight of its planes for Nato-led military operations against the Gaddafi regime, while Bulgaria sent a naval frigate to participate in a Nato operation to enforce an embargo on weapons destined for the Libyan regime.
And Nato allies agreed to establish a civilian post in Libya's eastern rebel bastion of Benghazi in an effort to step up political contacts with the opposition, an alliance source said.
The representative would likely be a diplomat from a Nato country that already has a presence in the rebel capital.
As the US and its allies pondered how to help the rebels, US President Barack Obama formally ordered a drawdown of $25-million in urgent, non-lethal aid to the Transitional National Council.
UN Secretary General Ban Ki-moon said Gaddafi's regime "has lost both legitimacy and credibility, particularly in terms of protecting its people and addressing their legitimate aspirations for change."