Libya's interim leader Mustafa Abdel Jalil has urged NATO to continue its Libya campaign until year's end, saying loyalists of slain despot Muammar Gaddafi still pose a threat to his country.

Abdel Jalil's comments, made at a Doha conference of military allies of his National Transitional Council, come a day after Gaddafi's body was buried in secret under cover of darkness after being displayed in public for four days.

"We hope (NATO) will continue its campaign until at least the end of this year to serve us and neighbouring countries," Abdel Jalil, NTC chairman, told the Conference of Friends Committee.

This request is aimed at "ensuring that no arms are infiltrated into those countries and to ensure the security of Libyans from some remnants of Gaddafi's forces who have fled to nearby countries," he added.

The NTC is also seeking help from NATO in "developing Libya's defence and security systems, Abdel Jalil told the conference.

In Brussels, diplomats said that NATO had decided to delay a formal decision to end Libyan air operations until Friday after the NTC's request for an extension and a Russian demand for UN consultations.

In the wake of Gaddafi's capture and death last week, NATO's decision-making body, the North Atlantic Council (NAC), had been expected to formally agree Wednesday to set October 31 as the date to end the seven-month-old air war.

"The NAC will meet with partners this Friday to discuss the Libya mission and take a formal decision," NATO spokeswoman Oana Lungescu told AFP.

US Defence Secretary Leon Panetta, on a visit to Japan, said that a future US military role in the new Libya would hinge on decisions by NATO.

And the United Nations urged Libya's new rulers to respect the rights of all detainees, amid raging controversy over the circumstances of the death of Gaddafi.

Meanwhile the last top figures of his ousted regime,Gaddafi's son Seif al-Islam and former intelligence chief Abdullah al-Senussi were poised to cross the border into Niger, a Tuareg official said.

Seif al-Islam was "near the Niger border, he hasn't entered Niger yet but he's close," a local official from the northern Niger Agadez region told AFP on condition of anonymity.

In June, the International Criminal Court issued arrest warrants against Gaddafi, Seif and Senussi for "crimes against humanity" allegedly committed by troops under their command as they quelled the uprising against his regime.

A Misrata military council member said Gaddafi was buried overnight Monday in a religious ceremony, along with another of his sons, Mutassim, and former defence minister Abu Bakr Yunis Jaber.

The bodies had been put on display in a market freezer on the outskirts of Misrata, a city 215 kilometres (132 miles) east of Tripoli, with thousands of Libyans queuing up since Friday to view and photograph them.

In Benghazi, a senior official of the NTC said the burial "took some time" to organise due to a "disconnect between the local (Misrata) council and the NTC."

According to guards at the entrance to the market, a convoy of four or five military vehicles took the bodies away to an unknown location, being kept secret to avoid the site turning into a rallying point for Gaddafi supporters.

Three Muslim religious figures loyal to the ousted dictator prayed and performed a religious ceremony before the burial, the Misrata council member said.

The two sons of the former defence minister, brought straight from prison, and his father were present to witness the bodies being picked up from the market, the source said.

The burials come as the circumstances of Gaddafi's death after he was taken alive last Thursday during the fall of his hometown Sirte -- the last holdout after an eight-month armed revolt -- continues to fuel controversy.

A UN human rights team set up to investigate rights violations in Libya said the NTC and armed groups in Libya should ensure that all prisoners are treated in line with international norms.

"In particular, I call on all the armed forces to avoid any act of reprisal and arbitrary repression against both Libyans and foreigners," Philippe Kirsch, the head of the International Commission of Inquiry on Libya, said in a statement.

The commission also welcomed decisions by the new rulers to probe the deaths "of certain detainees" -- an apparent reference to Gaddafi .

Abdel Jalil said  that a commission of inquiry will probe the strongman's killing.

Disquiet has grown internationally over how Gaddafi met his end after NTC fighters hauled him out of a culvert where he was hiding following NATO air strikes on the convoy in which he had been trying to flee his falling hometown.

Mobile phone videos show him still alive at that point.

Libya's interim premier Mahmud Jibril has said an autopsy report showed Gaddafi was killed in "crossfire from both sides."

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