Tripoli, Libya (CNN) -- Five days after he was taken into custody and then killed in his hometown of Sirte, ousted Libyan ruler Moammar Gadhafi was buried Tuesday, a National Transitional Council spokesman told CNN.
His body and those of his son Mutassim and his defense minister Abu Bakr Younis were interred in an undisclosed location, according to Anees al-Sharif, spokesman for the NTC's military arm in Tripoli.
The NTC and the United Nations have called for an independent investigation into the death Thursday of the man who ruled Libya for 42 years. Human Rights Watch, in a statement issued Monday, described Gadhafi and his son's deaths as "still unexplained."
Video shows that the elder Gadhafi was alive when he was captured.
In a statement, the NTC's executive office said Tuesday that it "attaches great importance to the concerted efforts deployed to ensure humane treatment, in accordance with the principles of international human rights covenants, to all Libyan and foreign prisoners and detainees. Under the supervision of the Ministry of Justice all cases and detention conditions will be considered and reviewed; fair trials will be guaranteed for those suspected of committing war crimes or criminal acts."
It said it had coordinated with the High Security Council, which oversees security units, "to ensure all prisoners and detainees are well treated until they are brought before the judicial authorities."
"We do not tolerate, and in fact we disapprove of any prisoner being hurt, let alone killed," the NTC said in a statement. "We did not want to end this tyrant's life before he was brought to court, and before he answered questions that have deprived Libyans from sleep and tormented them for years."
A NATO official said that Secretary-General Anders Fogh Rasmussen has repeatedly applauded Libya's new leaders for saying they are committed to human rights, the rule of law and reconciliation. NATO has "no way of verifying" the Human Rights Watch report and will not comment on it specifically, the official said.
Dubai-based Alaan TV aired what it called exclusive video showing the corpses of Gadhafi, his son Mutassim and Younis before burial "somewhere in the Libyan desert in the presence of about 20 people." The anchor said those in attendance said a prayer for dead before burying them.
The channel said attendees included members of the Misrata local council, a cousin of Moammar Gadhafi, two of Younis' sons, Gadhafi's driver and three tribal leaders loyal to Gadhafi.
Mahmoud Jibril, Libya's interim prime minister, has said Gadhafi's right arm was wounded when a gunbattle erupted between anti- and pro-Gadhafi fighters as his captors attempted to load him into a vehicle.
More shooting erupted as the vehicle drove away, and Gadhafi was shot in the head, dying moments before arriving at a hospital in Misrata, Jibril said, citing the city's coroner.
Libya's chief forensic pathologist, Othman el-Zentani, told CNN Tuesday that it would likely to be a week before he submits his findings into the deaths of Gadhafi, his son Mutassim and Younis to the attorney general's office.
The case is complex, he said, and much work remains to be done. Though the autopsies concluded Sunday, interviews must still be carried out and locations inspected, he said.
The bodies had been available for public viewing from a cold storage unit in recent days, except when they were being autopsied.
Gadhafi's family had issued a statement calling on the United Nations and Amnesty International to push Libya's new leaders "to hand over the bodies of the martyrs of their tribe so they can be buried according to Islamic rites," a pro-Gadhafi TV station reported.
A document purported to be Gadhafi's will was posted Tuesday on a pro-Gadhafi website. CNN could not verify its authenticity. In it, Gadhafi purportedly says he wishes to be buried in the clothes in which he died and according to Islamic law, in the cemetery in Sirte next to his relatives. He asks that his family be treated well, especially the women and children.
Urging the Libyan people not to relinquish the country's identity, history and achievements, the writer says: "I call on my supporters to continue resisting, and fighting any foreign aggressor against Libya, today, tomorrow and always.
"The people should know that we could have sold out our cause in return for a secure and stable life. We received many offers but we chose confrontation, duty and honor."
Meanwhile, U.S. Secretary of Defense Leon Panetta said that NATO may not end its mission in Libya -- due to wrap up October 31 -- as quickly as expected.
Speaking during a visit to Japan, he said: "I noticed today that there were comments from some of the Libya leadership asking that NATO continue its mission during this interim as they are trying to establish some of their governance."
Panetta said he would leave that decision to NATO but added that the United States was looking at how to provide medical assistance to wounded Libyans.
Human Rights Watch raised concerns Tuesday that the NTC was failing to secure "vast" stockpiles of explosive weapons discovered in recent days around the city of Sirte. It warned that such munitions could be used in terrorist attacks.
Two unguarded sites visited Saturday by representatives of the human rights group "contained surface-to-air missiles, tank and mortar rounds, large numbers of munitions, and thousands of guided and unguided aerial weapons," the group said.
CNN reporters in Libya have seen caches of unguarded weapons. The U.S. government said this month it had sent civilian experts to Libya to track down and destroy shoulder-fired, heat-seeking missiles it fears could be used to shoot down a civilian airliner. The U.S. experts are working alongside NTC teams to survey and secure weapons sites that had been under the control of Gadhafi's regime.
In its statement, Human Rights Watch said it had "found the remains of at least 95 people who had apparently died last Thursday. The vast majority had apparently died in the fighting and NATO strikes prior to Gadhafi's capture, but between six and 10 of the dead appear to have been executed at the site with gunshot wounds to the head and body."
"We saw a convoy, and in fact we had no idea that Gadhafi was on board," Lt. Gen. Charles Bouchard, commander of the NATO military operation, told reporters Monday. The convoy was carrying weaponry, and seemed to present "a clear threat to the population," he said.
The human rights group also said Monday that the bodies of 53 people, believed to be Gadhafi supporters, had been found in an abandoned Sirte hotel that was under the control of anti-Gadhafi fighters.
"Some had their hands bound behind their backs when they were shot," said Peter Bouckaert, the group's emergencies director.
Human Rights Watch investigators determined that the victims, who were being put into body bags in preparation for burial when they were discovered, appeared to have been killed between October 14 and 19.
In addition, medical officials in Sirte told Human Rights Watch that they had found 23 bound bodies between October 15 and 20 that were killed by pro-Gadhafi forces.
CNN could not independently verify these accounts about the bodies, their conditions, when they died and whom they may have supported.
The battle for the coastal city of Sirte, which was near Gadhafi's birthplace, was the final one in the months-long conflict in Libya. Aided by NATO strikes, opposition fighters first rooted in Benghazi went on to defeat Gadhafi loyalists throughout the country.
On Sunday, three days after Gadhafi's death, Libya's interim leaders declared the nation's freedom, with Jalil urging "honesty, patience and toleration" as the nation moves toward reconciliation.
CNN's Ingrid Formanek, Raja Razek and Claudia Rebaza contributed to this report.