Libya's provisional leaders have declared the country liberated from the 42-year rule of Moammar Gadhafi at a ceremony attended by tens of thousands of people in the eastern city of Benghazi.

National Transitional Council leader Mustafa Abdel Jalil told the crowd Sunday that Islamic law would be the main source of legislation in the post-Gadhafi Libya. He also urged Libyans to reject hatred as they begin to rebuild the country.

Jubilant Libyans filled the square, waving the red, black and green Libyan flag of the monarchy that Gadhafi overthrew in a 1969 coup.

Benghazi was the hub of the anti-Gadhafi uprising that began in February and ended when he was killed Thursday as provisional government forces defeated the former leader's die-hard loyalists in his hometown of Sirte.

In his speech, Mr. Jalil paid tribute to the thousands of protesters and opposition fighters who were killed in the uprising. He also gave thanks to NATO members and Arab nations who contributed military aircraft to a months-long campaign to protect Libyans from Gadhafi forces and help the rebellion.

In another address to the crowd, a Libyan government official responsible for helping victims of the conflict referred to Gadhafi as the “pharaoh” of the times and said he had fallen into the “garbage bin of history.”

International concern about the circumstances of Gadhafi's death stands in contrast to the celebratory mood inside Libya. Rights groups have called for an investigation into mobile phone video that shows provisional government fighters taunting and beating a wounded Gadhafi shortly before he died.

U.S. Secretary of State Hillary Clinton said Sunday that Washington would like to see a U.N. investigation of the killing and supports the investigation that Libya's NTC has pledged to conduct.

In an interview with U.S. television network NBC, she said it is important for a democratic Libya to begin with the rule of law and accountability. She said investigating Gadhafi's death should be a part of that process.

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

Libyan doctors performed an autopsy on Gadhafi's body in the city of Misrata Sunday and said he died of gunshot wounds to the head and abdomen. It is not clear who fired the shots that killed him. Libyan officials have said the former leader was shot in a crossfire between his loyalists and provisional government forces.

The body was on public display in a commercial freezer in Misrata Friday and Saturday. Details of his burial have not yet been disclosed.

Libya's outgoing provisional prime minister Mahmoud Jibril said Sunday consultations are under way to form an 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 was speaking on the sidelines of an economic forum in Jordan, where he also announced his resignation to allow new leaders to oversee Libya's transition to democracy.