Libya's interim leader Mustafa Abdel Jalil set a two-week target Monday for the country to have a new government and said a commission of inquiry is to probe Moamer Kadhafi's killing.
However, while the UN human rights office welcomed the Kadhafi inquiry, the United States urged Libya to also probe "extremely disturbing" allegations of summary executions of dozens of Kadhafi loyalists.
"We have begun talks (on forming a government), and this matter will not take a month but will be finished within two weeks," the National Transitional Council (NTC) chairman told a news conference in the eastern city of Benghazi.
A day after the NTC's declaration of Libya's liberation in the wake of Kadhafi's capture and death, Abdel Jalil also said a commission of inquiry is being set up to probe the controversial killing of the fallen strongman.
"In response to international calls, we have started to put in place a commission tasked with investigating the circumstances of Moamer Kadhafi's death in the clash with his circle as he was being captured," Abdel Jalil said.
The UN human rights office welcomed the announcement of a commission of inquiry.
"We stress the need to ensure that due process is followed, in accordance with international law, in the treatment of all detainees," said Ravina Shamdasani, spokeswoman for the UN High Commissioner for Human Rights.
After having raised concern in the West by stressing on Sunday that the new Libya will be governed in line with Islamic sharia law, the NTC chief gave assurances his country would remain a "moderate" Muslim country.
"I would like to assure the international community that we as Libyans are Muslims but moderate Muslims," he said.
The French foreign ministry said Paris will keep a watch over Libya's respect for human rights after the promise of a system of sharia to run post-Kadhafi Libya.
"We will be watchful of respect for human rights and democratic principles, notably cultural and religious diversity and the equality of men and women to which France is unswervingly attached," ministry spokesman Bernard Valero said.
And EU foreign policy chief Catherine Ashton said the introduction of sharia must respect human rights, while the State Department called on the new Libya to respect the rights of women.
Abdel Jalil's two-week timeline came as Libya's new leaders embarked on the task of forging an interim government uniting disparate political forces after 42 years of Kadhafi's iron-fisted rule, under which sharia took a back seat.
"Today, we begin preparing for a new phase... the phase after the liberation, the phase that we will plan and work hard for the future of Libya," said Abdel Hafiz Ghoga, vice chairman of the NTC.
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"Let us start work on the adoption of the constitution," he said Sunday as he declared liberation from Kadhafi's rule at a rally attended by tens of thousands of revellers in Benghazi, birthplace of the anti-Kadhafi revolt.
Under an NTC roadmap, an interim government is to be formed and then polls for a constituent assembly to draft a new basic law held within eight months -- the first democratic vote since Kadhafi came to power in a 1969 coup.
Parliamentary and presidential elections would be held within 20 months of Sunday's declaration.
The long-awaited liberation announcement came amid raging controversy over the circumstances of Kadhafi's death after he was taken alive during the fall of his hometown Sirte last Thursday.
Disquiet has grown internationally over how Kadhafi met his end after NTC fighters hauled him out of a culvert where he was hiding following NATO air strikes on the convoy in which he had been trying to flee his falling hometown.
Mobile phone videos show him still alive at that point.
The corpses of Kadhafi -- with a bullet wound to the head -- his son Mutassim, and decades-long confidant Abubakr Yunes still lay in a meat market freezer on the outskirts of the city of Misrata on Monday.
Since Friday, thousands of ordinary Libyans have viewed the bodies of the slain men, many taking pictures on their mobile phone.
"His cadaver has been kidnapped and exhibited as a war trophy, a conduct that violates the most elemental principles of Muslim norms and other religious beliefs," Cuban leader Fidel Castro wrote in an opinion column on Monday.
Libya's interim prime minister Mahmud Jibril said in Jordan on Sunday that an autopsy report showed Kadhafi was killed in "crossfire from both sides."
Human Right Watch, meanwhile, urged the NTC to probe the killing of 53 people whose decaying bodies were found in Sirte, where the pro-Kadhafi camp put up its final stand.
"We found 53 decomposing bodies, apparently Kadhafi supporters, at an abandoned hotel in Sirte," said Peter Bouckaert of Human Rights Watch (HRW), who investigated the killings.
"Some had their hands bound behind their backs when they were shot."
The US State Department urged Libya to probe the "extremely disturbing" report.
US Ambassador to Libya Gene Cretz "raised it with the Transitional National Council today and asked them to conduct a full investigation," State Department spokeswoman Victoria Nuland told reporters.
The head of operations in Libya for NATO, which has said it will wind down its seven-month mission by October 31, meanwhile, said that the country was now "essentially" free from threat of attack by Kadhafi loyalists.
"All areas have been freed," Lieutenant-General Charles Bouchard said at a video news conference from the operation's Naples operational headquarters. "The threat of Kadhafi remnants is essentially gone."