U.S. President Barack Obama won't release photos of Osama bin Laden after he was killed in Pakistan by Navy Seals because doing so would risk national security.

White House spokesman Jay Carney read excerpts of an interview that Obama did on Wednesday with the CBS show 60 Minutes to explain the decision to keep the photos classified.

Fake bin Laden photos emerge

The images are bloody, grotesque and convincing: Osama bin Laden lies dead, the left side of his head blasted away.

Unverified photos purporting to show bin Laden's corpse rocketed around the world on television and online almost as soon as his death was announced. The pictures have spread without regard for their origin or whether the images are real.

Newsrooms and the public are left in the tough spot of deciding what to believe when software has made doctoring photographs easier than ever. The hunger for visual evidence of bin Laden's death may only grow now that U.S. President Barack Obama has said the government's photos will remain classified.

The FBI warns that scammers may exploit that hunger by spiking digital bin Laden images with computer viruses.

Associated Press

"It is important for us to make sure that very graphic photos of somebody who is shot in the head are not floating around as an incitement to additional violence or as a propaganda tool…we don't trot out this stuff as trophies," said Obama, who saw the photos.

"This was somebody who was deserving of the justice that he received, and I think Americans and people around the world are glad that he is gone, but we don't need to spike the football, and I think that given the graphic nature of these photos, it would create some national security risk."

Defence Secretary Robert Gates and Secretary of State Hillary Clinton as well as Obama's intelligence teams all agreed with the decision, although CIA director Leon Panetta did not.

"We've done DNA sampling and testing, and so there is no doubt that we killed Osama bin Laden," Obama said. "Certainly there is no doubt among al-Qaeda members that he is dead and so we don't think that a photograph in and of itself is going to make any difference. There are going to be some folks who deny it.

"The fact of the matter is, you will not see bin Laden walking on this earth again."

At Obama's direction on Sunday, the U.S. launched a targeted attack against that compound in Abbottabad, which is about 150 kilometres north of Islamabad. Bin Laden was killed in a firefight.

Officials told The Associated Press that the Navy SEALs who stormed bin Laden's compound shot and killed him after they saw him appear to reach for a weapon.

The officials, who were briefed on the operation, said several weapons were found in the room where the terror chief died, including AK-47 assault rifles and side arms. The officials, who were not authorized to speak publicly, commented only on condition of anonymity.

After two days of shifting accounts of the dramatic raid, Carney said he would no longer provide details of the 40-minute operation by the team of elite Navy SEALs. That left unresolved numerous mysteries, prominent among them an exact accounting of bin Laden's demise. Officials have said he was unarmed but resisted when an unknown number of commandos burst into his room inside the high-security compound.

The officials who gave the latest details said a U.S. commando grabbed a woman who charged toward the SEALs inside the room. They said the raiders were concerned that she might be wearing a suicide vest.

Pakistan must have known: Afghanistan

The Afghan government said Wednesday that Pakistan must have known bin Laden was living in a military garrison town near the capital, echoing international suspicions about Islamabad in the aftermath of the deadly strike against al-Qaeda's chief.

"Not only Pakistan, with its strong intelligence service, but even a very weak government with a weak intelligence service would have known who was living in that house in such a location," said Defence Ministry spokesman Gen. Mohammad Zahir Azimi.

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Osama bin Laden during his time in hiding. ((Associated Press))

The house where bin Laden lived in the town of Abbottabad was close to the gate of the Kakul Military Academy, an army run institution where top Pakistani officers train, Azimi said, adding that many neighbouring houses are home to military officials.

Britain's Prime Minister David Cameron said bin Laden must have had an extensive support network in Pakistan in the years before his death. And Carney told reporters Tuesday that the U.S. is committed to co-operating with Pakistan despite questions about who in the Islamabad government may have known bin Laden was in hiding in the compound in Abbottabad.

The killing of bin Laden has sent public support for Obama sharply higher, the New York Times reported Wedneday. In all, 57 per cent of respondents to a Times/CBS News poll said they approved of his performance, up from 46 per cent a month earlier. And support seemed to cut across party lines, with both.

The Times noted, however, that former president George W. Bush got a similar bump after Saddam Hussein was defeated and killed, and it evaporated in a month.

U.S. Attorney General Eric Holder said Wednesday he has serious concerns about possible revenge attacks for bin Laden's death. He told senators during testimony that he thinks bin Laden's death ultimately will make the United States safer. Meanwhile, he's trying to address the risk that terrorists will avenge his killing.

After two days of speculation about releasing the photographs, there was no detectable public debate in the U.S. about the merits of the raid itself against the man behind the terror attacks that killed nearly 3,000 Americans on Sept. 11, 2001.

Holder told Congress the operation was "entirely lawful and consistent with our values" and justified as "an action of national self-defence." Noting that bin Laden had admitted his involvement in the events of nearly a decade ago, he said, "It's lawful to target an enemy commander in the field."

Holder also said the team that carried out the raid had been trained to take bin Laden alive if he was willing to surrender.

"It was a kill-or-capture mission," he said. "He made no attempt to surrender."

Officials said bin Laden had money as well as two telephone numbers sewn into his clothing when he was killed, suggesting he was prepared to leave on a moment's notice if he sensed danger.

With files from The Associated Press