Libya's transitional leader says he hopes talks to form a new interim government will be finished in about two weeks.

National Transitional Council head Mustafa Abdel Jalil made the remark in the eastern city of Benghazi Monday, a day after he declared the country liberated from Moammar Gadhafi's 42-year rule at a ceremony attended by tens of thousands of people.

Mr. Jalil also said Monday the NTC has ordered an investigation into Gadhafi's death after the U.S. government, rights groups and others called for the probe.

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 during last week's takeover of Sirte. Cell phone video shows provisional government fighters taunting and beating a wounded Gadhafi shortly before he died.

Libyan officials said 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 Monday. Details of his burial have not been disclosed.

Meanwhile, a human rights group is asking Libya's new authorities to investigate a possible mass execution of suspected Gadhafi supporters during the battle for Sirte.

Human Rights Watch says it found the bodies of 53 people who appear to have been executed in an area that was controlled by NTC fighters 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, an abandoned hotel.

Sirte residents preparing the bodies for burial said most of the victims were local people and some were Gadhafi supporters.

France said Monday it would keep watch on Libya's respect for human rights. A French foreign ministry statement said it is confident of the Libyan people's ability to construct a state of law that conforms to the “universal values shared by the international community.”