The US is holding an inquiry into how photos of Saddam Hussein were leaked to UK newspaper the Sun, which has now printed more pictures of him.
The Sun says this is an "extraordinary iconic news image"
The US military vowed to "aggressively" investigate how the photos of Iraq's ousted leader appeared in the paper.
After printing images on Friday of Saddam Hussein in his underpants and doing his washing, its Saturday edition pictured him behind barbed wire.
The paper has defended its decision to publish the photos.
It said they were obtained from a US military source.
The Sun's new photos show Saddam Hussein fully dressed, in a white robe-like garment, in a prison compound.
The newspaper also ran photos of two top members of the former Iraqi regime, who were identified as Ali Hassan al-Majid, better known as "Chemical Ali" and Huda Salih Mahdi Ammash dubbed "Mrs Anthrax".
It said it would fight any legal action after Saddam Hussein's chief lawyer pledged to sue the newspaper.
'Barbaric and backwards'
US President George W Bush said he did not think the photos would encourage insurgents in Iraq.
"I don't think a photo inspires murderers. I think they're inspired by an ideology that's so barbaric and backwards that it's hard for many in the Western world to comprehend how they think."
However, several Arab commentators have suggested the photos could increase anti-American feeling in the region.
The Arabic satellite network, al-Jazeera, did not show the photo of Saddam Hussein in his underpants, saying they were "not news". However, al-Arabiya TV did include the picture in its bulletins.
'Breaching Geneva convention'
A statement from the US military on Friday said it was "disappointed at the possibility that someone responsible for the security, welfare, and detention of Saddam would take and provide these photos for public release".
The US military and legal experts also said the photos - possibly taken more than a year ago - may breach Geneva Convention rules on the humane treatment of prisoners of war.
The conventions say countries must protect prisoners of war in their custody from "public curiosity".
Saddam Hussein is being held by US troops at an undisclosed location in Iraq as he awaits trial on numerous charges, including murdering rivals, gassing Iraqi Kurds and using violence to suppress uprisings.
Friday's photos showed the 68-year-old former leader with a moustache, rather than the beard he sported when he was captured in December 2003, and again when he appeared in court last July.
The Sun's front page showed him wearing a pair of white underpants in his prison cell.
Other pictures showed him washing his trousers, shuffling around and sleeping.
The photos also appeared in the New York Post, which - like the Sun - is owned by media mogul Rupert Murdoch.
Defending the decision to publish, the Sun's managing editor Graham Dudman said: "People seem to forget that this is a man who is responsible for the deaths of hundreds of thousands of men, women and children and all that's happened to him is someone has taken his picture," he told BBC Radio 4's PM programme.
"This is a sort of modern-day Adolf Hitler. These pictures are an extraordinary iconic news image that will still be being looked at the end of this century."