President Barack Obama has changed his mind and will attempt to block publication of photographs showing the abuse of terrorism suspects by US soldiers.
The government previously said it would not fight a court ruling ordering the release of the pictures.
President Obama now says the publication of the photos would make the job of US troops in Iraq and Afghanistan more difficult.
The pictures were due to be released by 28 May, according to a ruling by the US Court of Appeals, in response to a request by the American Civil Liberties Union.
The dispute could now end up before the US Supreme Court.