As Libya's new rulers are scheduled to announce over the weekend the "liberation" of the country after the death of fallen leader Muammar Gaddafi, mist still exists over the burial of the former leader as well as the whereabouts of his second-eldest son Saif al-Islam.

After Gaddafi was captured alive but died of bullet injuries in his hometown Sirte in northern Libya, his body has been transferred to Misrata, a town which suffered heavily during clashes between Gaddafi's forces and fighters of the now ruling National Transitional Council (NTC).

In spite of reports shortly after Gaddafi's death that he should be buried on Friday in accordance with Islamic traditions, his body is still kept in a commercial freezer in a shopping center in Misrata, located between Sirte and the capital Tripoli, in a bid to prevent angry civilians from taking revenge on the dead body of the country's top figure for over four decades.

Earlier on Friday, a source close to the NTC's information office told Xinhua that it is possible that the burial would be delayed for some time due to discussions among Libya's new rulers.

More accurate investigations will take time, the source said. However, senior NTC leaders are yet to confirm on either the date or a delay.

In the meantime, an official of Misrata's military council, who asked not to be named, told Xinhua Friday that discussions were still underway on the ritual, date and location for the burial of Gaddafi, with some people proposing Gaddafi be buried at sea.

Less than half a day after Gaddafi's death on Thursday, Mahmoud Jibril, head of the NTC's executive committee, told reporters that Gaddafi's body might be buried in Libya or abroad, but one certain thing is that it would be in an undisclosed location.

Jibril said the coroners have collected the DNA samples of Gaddafi and his fourth son Mutassim, who was also captured in Sirte Thursday but died soon after in murky circumstances. He said forensic reports would be attached with pictures for submission to the International Criminal Court.

The United Nations on Friday called for a comprehensive investigation into Gaddafi's death to make clear that whether the former Libyan leader was killed in purpose by the NTC fighters, after Gaddafi's widow Safia requested a look into the circumstances of her husband's death through the Syria-based Arrai TV channel, the sole remaining pro-Gaddafi media which has broadcasted episodes of Gaddafi's sound recordings after he was driven away from the capital nearly two months ago.

However, senior NTC leaders including Jibril have been stressing since Thursday that Gaddafi was captured alive and suffered only a shot in his right hand before being sent onto a NTC pickup truck, and that it was the "crossfire between the revolutionaries and the (Gaddafi) loyalists" later that ended up with a shot in Gaddafi's head.

Jibril cited doctors as saying that there was not any sign of blows or bruises on the face of Gaddafi, who was still alive a few minutes before his arrival at the hospital.

Meanwhile on Friday, doubts also surround the fate of Saif al- Islam, a most likely successor to his father. Reports by pan-Arab Al Arabiya channel on Friday said a NTC field commander told the channel that Saif al-Islam had been captured in the Libyan city of Zeltin, 160 km east of Tripoli.

The commander named Ali el-Shawesh was quoted as saying that Saif al-Islam was captured in the south of the city and was undergoing medical treatment.

Similar information was provided by a field commander, who identified himself as Frajj, from Libya's second largest city of Benghazi.

When addressing a crowd at the Martyr's Square in Tripoli on Friday evening, the commander said that Saif al-Islam was captured in Zeltin and suffered wounds in one arm and one leg. However, official confirmation from senior NTC officials is currently unavailable. And no pictures or footage that could prove Saif al- Islam was under arrest have been released so far.

In the meantime, on Friday, NATO Secretary General Anders Fogh Rasmussen said the military alliance's Libya mission is very close to completion, and that it has taken a preliminary decision to end it on Oct. 31.

The NATO-led Western coalition has assisted the Libyan NTC fighters in their fight against the Gaddafi forces with their air operations destroying much of Gaddafi's military facilities across the country since March this year.

"We will take a formal decision next week. In the meantime, I will consult closely with the United Nations and the (Libyan) National Transitional Council," Rasmussen told a press conference in Brussels.

"We agreed that NATO will wind down the operation during a quick period, that means until Oct. 31," he said.

However, NATO would continue to monitor the situation in Libya and retain capability to respond to threats against Libyan civilians if needed, during the phasing out period of its mission, he added.