Washington: The United States on Friday urged Libyan's interim leaders to provide "a transparent account" of the death of strongman Muammar Gaddafi.

The National Transitional Council "has already been working to determine the precise cause and circumstances of Gaddafi's death and we obviously urge them to do so in an open and transparent manner as we move forward," State Department spokesman Mark Toner said.

"We also continue to urge them, as we have been over the past months, to treat prisoners humanely," Toner added.

US President Barack Obama said on Friday that Gaddafi's death ended decades of "iron fist" rule in Libya and warned Arab tyrants that it showed their brutal regimes would inevitably fall.

"This is a momentous day in the history of Libya," said Obama, adding that "the dark shadow of tyranny has been lifted."

But Libya's leaders were under pressure on Friday to proclaim the country's liberation and move toward democracy, amid euphoria over Gaddafi's death despite still murky circumstances.

With suggestions, including from Russia, that the deposed dictator may have been summarily executed after his capture, Moscow, the UN human rights chief and Amnesty International called for an investigation.

The National Transitional Council, Libya's new rulers, had been expected to issue a promised declaration that the country was finally freed following the death of Gaddafi, his son Mutassim and other top regime figures, and the fall of his hometown Sirte.

US drone involved in Gaddafi strike

US officials say an American Predator drone was involved in the airstrike that hit the convoy carrying ousted Libyan leader Muammar Gaddafi, but it is not clear how he got his fatal wounds.
US Officials said the Predator fired on the convoy as it was fleeting Sirte, and French aircraft launched guided missiles. According to most accounts two vehicles in the convoy were hit.
Gaddafi was wounded when captured, but later died. He had gunshot wounds to his head, chest and stomach.
The officials spoke on condition of anonymity because of the sensitivity of the operations. NATO's top commander said on Friday he will recommend ending the alliance's seven-month
mission in Libya.
American ships and aircraft involved in the Libya mission are still there, but many will likely move on.

Libyan fighter claims killing Gaddafi

A young Libyan fighter has claimed in a video posted on the Internet that he had captured Libya's deposed leader Muammar Gaddafi and shot him twice, fatally
wounding him.
The claim, made by a youth from Benghazi identified as Sanad al-Sadek al-Ureibi, added fuel to growing speculation over how Gaddafi died on Thursday.
It also seemingly contradicted claims by Libya's ruling National Transitional Council that Gaddafi was shot in the head when he was caught "in crossfire" between his supporters
and new regime fighters soon after his capture.
On the video, Ureibi, said to have been born in 1989, is shown being interviewed by a number of unidentified men, some of them wearing military fatigues, who are congratulating him.
They showed to the camera a gold ring and a bloody jacket allegedly belonging to Gaddafi, with the ring being engraved with the name of Gaddafi's second wife, Safia, and the September 10, 1970, date of their marriage.
"I fired two bullets at him, one hit under his armpit, the other his head. He did not die immediately. It took him half an hour," he said.

He described being separated from members of his brigade in Benghanzi and his decision to join fighters in Misrata when new regime forces assaulted Sirte, Gaddafi's hometown.
"We came across Gaddafi in a street, as he was walking with some children and girls.”
"He was wearing a hat. We recognised his hair, and a fighter from Misrati said to me, 'That's Gaddafi; let's get him'."
Ureibi said he neutralised the ex-Libyan leader, who was carrying a gold pistol, by grabbing his arms.
"I slapped him. He said to me 'you are like my son.' I slapped him a second time. He said, 'I am like your father.' Then I grabbed him by the hair and put him on the ground."
He said he wanted to take Gaddafi to Benghazi, but when Misrati fighters insisted on taking the fallen leader back to their city, he decided to open fire and shot Gaddafi twice.
He said the Misrata fighters confiscated his pistol and threatened him with death if he returned to Libya's third city.

Desmond Tutu slams Gaddafi violent death

South African peace icon Desmond Tutu on Friday decried the violent death of Muammar Gaddafi, saying Libyans should have shown "better values" than the
dictator who oppressed them for 42 years.
"Mob justice and violence should always be deplored," the 80-year-old Nobel Peace Prize laureate said in a statement.
"The manner of the killing of former dictator Muammar Gaddafi on Thursday totally detracts from the noble enterprise of instilling a culture of human rights and democracy in Libya."
The killing of a human being is not something to be celebrated, he said.
"And the people of Libya should have demonstrated better values than those of their erstwhile oppressor," added Tutu.
"The United States Secretary of State, Ms Hillary Clinton, cannot be proud of her call for his killing," he said.
Clinton in July warned that the strongman's "days are numbered".

Gaddafi who ruled the oil-rich North African country for 42 years was killed on Thursday in crossfire between his supporters and new regime fighters after his capture in his hometown of Sirte.
Tutu was a leading figure in the fight against South Africa's white-minority regime, winning the Nobel Peace Prize in 1984 for his non-violent struggle against apartheid.