Libya's National Transitional Council has delayed the burial for Muammar Gaddafi in order to arrange a secret location and allow for an investigation into his death, officials say.

On Friday, as videos continued to surface showing the fugitive deposed leader being captured alive by a crowd of NTC fighters, the United Nations' human rights office added its voice to calls for an investigation into how Gaddafi died.

"Taken together, they were very disturbing," Rupert Colville, spokesman for the office of the UN High Commissioner for Human Rights, said of the images.

Gaddafi's body is being kept in a cold storage site in Misrata, where it was taken after NTC fighters captured and killed him in his hometown Sirte on Thursday. It bears a bullet hole in the head, the Reuters news agency reported.

Al Jazeera's James Bays, reporting from Tripoli, said NTC officials were discussing behind the scenes how the event would take place and who would represent the Gaddafi family and his tribe.

He said officials were keeping the media at arm’s length in the hope that the location of Gaddafi’s final resting place could be kept secret.

Liberation

But other details about the country's political road ahead have begun to emerge. The NTC says it will declare the full "liberation" of Libya on Sunday, after initially saying it would take place on Friday, then on Saturday.

Mahmoud Shammam, the NTC's information minister told reporters: "It will be a public announcement, I think in the main square of Benghazi by (NTC chairman) Mustafa Abdel Jalil. It will be on Sunday afternoon at around 14:00 GMT.

The city of Benghazi in Libya's east is regarded as the cradle of the revolution and has been a stronghold for NTC fighters and the base of NATO operations.

The announcement is set to mark what the NTC says will be the beginning of the process of building a democratic system in Libya after a four decade rule by the slain strongman, whose death still divides a nation.

Speaking about the way forward, Bays said the first step toward rebuilding Libya would be an official declaration of liberation, expected to take place on Saturday in Benghazi, the eastern city that became the headquarters of the revolt against Gaddafi.

A newly formed interim government, headed by a new prime minister to replace Mahmoud Jibril, would then lead Libya towards elections, expected to take place in eight months.

The new prime minister would have to balance competing groups and factions in Benghazi, Tripoli and Misrata, as well finding common ground between the political and military bases that steered the revolution through, Bays said.