"The concern was the release of those photos could have a negative impact on the situation both in Iraq and in Afghanistan and I think the president as commander in chief ... thought that the posture he has now put us in was the better one."

'Inflaming opinion'

In depth

  Video: Abuse 'unprecedented'
  Obama blocks abuse images

The US department of defence was to release the images by May 28 in response to legal action filed by the American Civil Liberties Union (ACLU).

But Obama said the government would appeal the legal ruling ordering the release of the photos, which reportedly depict abuse of detainees in Afghanistan and Iraq.

The move means the case could now be decided by the US supreme court.

"The most direct consequence of releasing them, I believe, would be to further inflame anti-American opinion and to put our troops in greater danger," Obama told journalists on Wednesday.

"Moreover, I fear the publication of these photos may only have a chilling effect on future investigations of detainee abuse."

'No validity'

Jonathan Hafetz from the ACLU told Al Jazeera on Thursday there was "no validity" to the government's argument and that the US public had a right to know what had occurred.

"Secrecy is fundmantally inconsistent with America values and the rule of law," he said.

"It undermines not enhances our security to try to shield abuses that we have committed from the public eye."

The photographs come from more than 60 criminal investigations between 2001-2006 and are of military personnel suspected of abusing detainees, officials said in April.

The release of photos of abuse of Iraqi detainees at Abu Ghraib prison in Iraq in 2004 caused widespread anger.

The administration of George Bush, the previous US president, had argued against the release of the photos in part by saying it violated the privacy rights of the detainees and military personnel.

Pelosi row

Pelosi has faced criticism for not
speaking out against waterboarding [EPA]
As the row on torture pracitices under the Bush administration continued, Nancy Pelosi, the speaker of the US House of Representatives, accused the CIA of misleading Congress over the use of waterboarding, which simulates the sensation of drowning.

Pelosi said the CIA had told her they were not using the practice when she was informed about it in September 2002, despite since admitting they had used it then, she said.

"The only mention of waterboarding at that briefing was that it was not being employed," she said.

The Democrat politician had faced criticism for not speaking out against the practice earlier.