A human rights group reporting from the hometown of ousted Libyan leader Moammar Gadhafi says it has found the bodies of 53 people who appear to have been executed by fighters for the National Transitional Council during the bitter fighting for control of the city.

Humans Rights Watch said Monday it discovered the bodies in an abandoned hotel in an area of Sirte that was controlled by anti-Gadhafi forces at the apparent time of the deaths about a week earlier. The group said the bloodstains on the grass, the bullet holes on the ground and the bullet casings scattered around the site suggest that executioners killed some, if not all, of the people at that location.

Sirte residents preparing the bodies for burial said most of the victims were local people and some were Gadhafi supporters. Human Rights Watch is urging Libya's new authorities to investigate the deaths and hold those responsible accountable.

Libya's provisional authority on Sunday declared the country liberated from Gadhafi's 42-year rule. Tens of thousands of jubilant people gathered for the ceremony in the eastern city of Benghazi.

NTC head Mustafa Abdel Jalil told the crowd that Islamic law would shape the new constitution in post-Gadhafi Libya.

Libya's outgoing provisional prime minister, Mahmoud Jibril, said consultations are under way to form a new interim government within one month, followed by elections for a constitutional assembly within eight months. Parliamentary and presidential elections would be held within a year after that.

Jibril spoke from an economic forum in Jordan, where he announced his resignation to allow new leaders to oversee Libya's transition to democracy.

Concerns still linger about the circumstances of the death of Moammar Gadhafi in Sirte on Thursday. Cell phone video showed provisional government fighters taunting and beating a wounded Gadhafi shortly before he died.

U.S. Secretary of State Hillary Clinton says the United States would like to see a U.N. investigation of Gadhafi's killing. She said she supports the investigation that the NTC has pledged to conduct, and said it is important for a democratic Libya to begin with the rule of law and accountability.

British Defense Secretary Philip Hammond said Gadhafi's killing had “stained” the image of Libya's provisional government, and that Britain would have liked to see the former leader stand trial for alleged misdeeds.

Libyan doctors performed an autopsy on Gadhafi's body in the city of Misrata and said he died of gunshot wounds to the head and abdomen. Libyan officials say the former leader was shot in a crossfire between his loyalists and provisional government forces. Fighters on the scene have acknowledged beating the ousted leader after his capture.

Gadhafi's body remained on public display in a commercial freezer in Misrata Sunday. Details of his burial have not been disclosed.