Senegalese President Abdoulaye Wade, meanwhile, urged Libyan leader Moamer Kadhafi to step down, "the sooner the better," as he became the first head of state to visit the rebels' eastern bastion of Benghazi.
US Secretary of State Hillary Clinton and counterparts from NATO and other countries participating in air strikes against Kadhafi's forces wound up talks on Libya in the United Arab Emirates capital Abu Dhabi.
"Kadhafi's days are numbered. We are working with our international partners through the UN to plan for the inevitable: a post-Kadhafi Libya," Clinton told participants, according to her prepared remarks.
"Time is on our side," she said, adding the international military, economic and political pressure was mounting on the Libyan colonel to abandon his four decades in power.
"In the days ahead," she said, "we have to coordinate the many plans taking shape and work closely" with the rebels' NTC and Libya's people.
Clinton said "people close to Kadhafi" have been making continuous contacts with many different interlocutors about the "potential for a transition" to a new regime.
"There is not a clear way forward yet," the chief US diplomat told a news conference.
But she said the international community must over the next month, when more talks on Libya are held in Istanbul, make "sure that all of those contacts are understood and evaluated because they occur with many different interlocutors."
In Washington, US defence secretary nominee Leon Panetta said there were signs Kadhafi may be toppled due to the sustained diplomatic, economic and military pressure on his regime.
"I think there are some signs that -- if we continue the pressure, if we stick with it -- that ultimately Kadhafi will step down," Panetta told the Senate Armed Services Committee in a confirmation hearing.
Amid growing diplomatic support for the NTC, Clinton also called the council "the legitimate interlocutor" of the Libyan people as US President Barack Obama's administration sought to promote a peaceful transition process.
But she offered no direct US financial contribution to the rebels, pledging instead another "$26.5 million to help all the victims of this conflict."
US officials said the United States would urge Arab countries to offer more funds to the rebel administration.
Libya's former foreign minister and envoy to the United Nations, Abdurrahman Shalgam, told journalists the NTC needs at least three billion dollars over the next four months for current expenses.
Italian Foreign Minister Franco Frattini said Rome would provide the rebel council with loans and fuel products worth 300 to 400 million euros ($438 million to $584 million).
His French counterpart, Alain Juppe, said his government would release 290 million euros ($420.9 million) of frozen Libyan funds for the benefit of the NTC.
A member of the NTC said in Abu Dhabi that an international fund aimed at helping Libya's rebels had "become operational" from Thursday.
A State Department official told reporters "we have got commitments of something about 300 million dollars that came out of today's meeting," including 180 million dollars from Kuwait and 100 million from Qatar.
At the UN Human Rights Council in Geneva, Libya rejected charges it committed crimes against humanity in a crackdown in February on anti-regime protests, which it said triggered the armed insurgency against Kadhafi's rule.
"The protests only lasted for a few hours on 15 February. This was dealt with by Libya without any human rights abuses," Mustafa Shaban, Libya's head of delegation, told the council.
On the battlefront, explosions continued to rock Tripoli.
Four blasts shook the capital on Thursday afternoon after explosions echoed through the city from near Kadhafi's compound overnight.
NATO said it hit an electronic warfare vehicle and a military training camp near Libya's third-largest city Misrata.
The Mediterranean city is the most significant rebel-held enclave in western Libya and a rebel spokesman said up to 3,000 Kadhafi troops attacked it in a three-pronged movement from the south, west and east on Wednesday.
Twelve people were killed and 33 wounded in the fighting in which Kadhafi's forces deployed gunships, tanks and Grad rocket launchers as well as mortars, the spokesman, Hassan al-Galai, told AFP by telephone.
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