Libya's rebels declared the "Kadhafi era" over after taking control of most of Tripoli as US President Barack Obama called for "an inclusive transition" in the war-torn country.
Obama pressed Libya's veteran strongman Moamer Kadhafi, who has refused to surrender, to "explicitly" give up power and warned exuberant rebels that their struggles were "not over yet."
Looking beyond Kadhafi's iron-fisted reign, he vowed that Washington will be "a friend and a partner" and urged "an inclusive transition that leads to a democratic Libya."
The White House, meanwhile, said it had "no evidence" that Kadhafi had left Tripoli. "That is the best information that we have," spokesman Josh Earnest told reporters. "There's no evidence to indicate that he's left."
"The Kadhafi era is over," rebel chief Mustafa Abdel Jalil told a news conference in Benghazi, eastern Libya.
But Seif al-Islam Kadhafi, once seen as the possible successor, was in Kadhafi's residential complex in Tripoli early Tuesday and seen by an AFP correspondent despite earlier reports he had been arrested by rebels.
"I am here to refute the lies," the 39-year-old said in the heavily-guarded complex where three journalists, including AFP, were driven by regime forces.
"Tripoli is under our control," he added.
Luis Moreno-Ocampo, the prosecutor of the International Criminal Court which had issued arrest warrants for Seif al-Islam earlier said he had information that he was being held by rebels.
Mohammed Kadhafi, Kadhafi's eldest son, whose arrest had also been announced, has escaped, the Libyan ambassador to Washington told CNN.
Ali Suleiman Aujali with the Libyan rebel National Transitional Council (NTC) told CNN that Mohammed was apparently taken by "maybe Kadhafi's forces." A senior rebel source confirmed the escape to AFP, saying "Yes, it's true, he has escaped." The source in the rebel capital of Benghazi, eastern Libya, spoke on condition of anonymity.
Rebel leader Abdel Jalil said meanwhile he hoped Kadhafi, who faces an arrest warrant issued by the International Criminal Court for alleged crimes against humanity, would be "captured alive so that he will be given a fair trial."
He thanked NATO for its military support, while cautioning that "the real moment of victory is when Kadhafi is captured" and acknowledged the whole of Tripoli was not under rebel control.
In another military setback for Kadhafi, his forces quit the frontlines of the eastern oil town of Brega on Monday and were fleeing west towards the strongman's hometown of Sirte, a rebel military spokesman said.
Mohammed Zawiwa told AFP the rebels seized control Monday of the state broadcaster in Tripoli.
"All the television stations controlled by the state have stopped transmitting (in Tripoli). Our fighters have gone in and taken control of the facilities," Zawiwa said.
Elsewhere in Tripoli, rebel fighters packed in trucks, cars and pickups streamed during the day from liberated areas of western Libya towards the symbolic Green Square in the heart of the city, brandishing arms.
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Many of the rebels waved flags of the revolution as they appeared to be heading to the square and then onwards to join rebels trying to snuff out the last pockets of resistance, especially outside Kadhafi's Bab al-Azizya compound in Tripoli.
Rebel chief Abdel Jalil said it was difficult to tell whether Kadhafi has fled the country or remained within, pointing out that he could still be at his compound.
"The area around Al-Azizya is still a hot spot. There are forces that continue to fight the rebels. He (Kadhafi) could still be in Al-Azizya, or in neighbouring areas," he said.
Foreign correspondents based in the capital's Rixos hotel, separated by a wooded area from Kadhafi's residence, said the atmosphere was tense late on Monday but without reporting any major confrontation.
Kadhafi broadcast three defiant audio messages on Sunday, vowing he would not surrender and urging the people of Tripoli to "purge the capital," even as rebel forces swept through the capital and took over waterfront Green Square.
But he has not been seen in public for weeks.
France welcomed the apparent defeat of Kadhafi's regime and said it would host a summit of the international "Contact Group" coordinating a response to the conflict. Reaction: World leaders hail end of Kadhafi regime
Diplomats from the Contact Group will first meet on Thursday "to coordinate next steps," the US State Department said.
In London, British Prime Minister David Cameron said Kadhafi's regime was in "full retreat" and he should give up any hope he has of clinging on to power.
Thousands of residents poured onto the streets of Tripoli Sunday night to welcome the rebels, congregating at Green Square, which they renamed Martyrs Square.
Many waved the red, black and green flag of anti-regime forces, dancing in joy and shouting Allahu Akbar (God is greatest). Some fired rifles into the air.
Similar scenes of jubilation were witnessed in Benghazi, the rebels' bastion in the east, where tens of thousands of delirious residents danced and proclaimed the end of the regime of the "tyrant" Kadhafi.
UN leader Ban Ki-moon said the heads of the African Union, European Union, Arab League and other regional groups would attend a summit on Libya later this week in New York.
The International Organisation for Migration (IOM), meanwhile, said that it had dispatched a ship with a capacity to carry 300 people to Tripoli to evacuate migrants.
"The boat, the Tasucu, is due to arrive in Tripoli on Tuesday and will leave for Benghazi as soon as IOM is able to successfully board the migrants," said the inter-governmental agency.
Aides to Kadhafi had made "desperate" attempts to negotiate with US officials just before the massive offensive that the rebels mounted at the weekend, US officials said Monday.
"There have been lots of feelers from lots of folks claiming to represent Kadhafi," including "more desperate ones in the last 48 to 24 hours," State Department spokeswoman Victoria Nuland told reporters.
"But none of them were serious because none of them met the standard that we insist on, that the international community insisted on, which is to start with his willingness to step down," Nuland said.