|Mustafa Abdel Jalil, Libya's interim leader, thanked the UN for its sanctions against Muammar Gaddafi [AFP]
Barack Obama, the US president, has led an international welcome for Libya's new interim leaders at the UN, promising that NATO would carry on with air strikes while civilians are "threatened".
With the new Libyan flag flying at the UN headquarters in new York on Tuesday, interim government leader Mustafa Abdel Jalil thanked all nations who aided with the "success of the Libyan revolution" which he said had left at least 25,000 people dead.
Al Jazeera correspondent Mike Hanna, reporting from New York, described the UN welcome as "very significant" and noted how much the international image of Libya has changed.
"It's also an indication of how fast things can change; just seven months ago Jalil was the justice minister serving under Gaddafi. And it was Gaddafi who stood up and spoke contemptuously to the [UN] at one point towssing aside its charter. Now, his former justice minister is here in his place," said Hanna.
The UN and world leaders promised to help the new government with its campaign to take remaining territory held by fighters loyal to deposed leader Muammar Gaddafi and to rebuild the country and organise elections.
"For the past seven months, you have fought courageously for your fundamental rights and freedoms," Ban Ki-moon, the UN secretary-general, told Jalil.
'Inclusive and just'
Amid new battles for towns still in the hands of Gaddafi loyalists, Ban said "the first priority must be peace and security", while Obama called on those fighters still supporting Gaddafi to lay down their arms.
"So long as the Libyan people are being threatened, the NATO-led mission to protect them will continue," Obama said.
"And those still holding out must understand - the old regime is over, and it is time to lay down your arms and join the new Libya.
"Today, the Libyan people are writing a new chapter in the life of their nation. After four decades of darkness, they can walk the streets, free from a tyrant."
The US president described Libya as "a lesson in what the international community can achieve when we stand together as one".
But he stressed that there must be a democratic transition after four decades of one-man rule that is "peaceful, inclusive and just".
"To the people of Libya: this is your chance," Obama said. "And today the world is saying, in one unmistakable voice, we will stand with you as you seize this moment of promise; as you reach for the freedom, the dignity and the opportunity you deserve."
As Al Jazeera's Hanna pointed out, not all members of the UN have recognized the NTC as the legitimate government of Libya.
"The process is still not complete in terms of getting total international recognition, but they do have the backing of the major states and the UN Security Council," Hanna said.
"It's a very important public endorsement, especially from Obama," he added.
Jalil, who now head the National Transitional Council (NTC), told the UN summit how the revolution had left 25,000 "martyrs" and at least 50,000 wounded during the eight months of fighting.
He thanked the UN, which passed sanctions against Gaddafi, and all the countries that helped "the success of the Libyan revolution".
Without mentioning the NATO airstrikes, he said international assistance had been crucial because of the "huge amount of weaponry that Gaddafi deployed against his people".
Jalil vowed that the new Libya would be a "vibrant" democracy that respects regional peace and security.
Al Jazeera correspondent Hashem Ahelbarra, reporting from Triploi, said the UN welcome will "provide a boost" for the NTC's authority in Libya and may help morale as its forces fight to capture the final Gaddafi strongholds.
"Once Jalil is back in Libya, the focus must be on forming a new government," Ahelbarra added.
The NTC chairman said many Gaddafi regime members had been detained and some had been freed again.
Jalil said many would face justice and all would get a "fair trial".
French President Nicolas Sarkozy made a plea for support for all of the Arab countries where people have stood up against authoritarian leaders.
"When we saw the people taking to the Arab streets to call for liberty and democracy we took some time to respond as we were astonished at what we were seeing," Sarkozy said.
He said the Arab demonstrations had given the international community a "responsibility to take action".
Sarkozy indicated that the action in Libya, as well as UN action in Ivory Coast, this year should be a warning to other strongarm leaders.
"Henceforth the international community is not just going to speak, but will take action and where necessary will take action with weapons in their hands in the service of democracy," he told the summit.
Also on Tuesday, the African Union recognised the NTC as Libya's de facto government, removing another piece of diplomatic support for Gaddafi.
The pan-African body, which has frequently been criticised for its ponderous reaction to events on its doorstep, said in a statement it was ready to support the NTC in its efforts to build an inclusive government.
It also urged the NTC to protect African migrant workers, following reports of black Africans being targeted by armed groups hunting down mercenaries loyal to Gaddafi.