President George W Bush has said his embattled Defence Secretary Donald Rumsfeld is doing a "superb job".
The latest pictures show detainees being threatened with dogs (AP Photo/Courtesy of The New Yorker)
Speaking to reporters after a briefing at the Pentagon on the situation in Iraq, Mr Bush thanked Mr Rumsfeld for his leadership.
He also promised a "full accounting" for the "cruel and disgraceful" treatment of Iraqi prisoners.
Mr Bush's praise of Mr Rumsfeld came amid growing calls for the defence secretary to resign over the scandal.
With Mr Rumsfeld at his side, Mr Bush said the defence secretary was "courageously leading our nation in our war against terror".
"You are a strong secretary of defence and our nation owes you a debt of gratitude," Mr Bush told him.
Mr Bush had just come out of a meeting with national security officials and top generals in charge of operations in Iraq.
The White House said the meeting had been scheduled well before the scandal surrounding the mistreatment and humiliation of inmates erupted, but the abuse was a key part of the briefing.
President Bush was shown more than a dozen photographs and still images from video of US military guards apparently abusing Iraqis. White House spokesman Scott McClellan declined to describe the content of the images, but said Mr Bush was disgusted by them.
Pentagon officials say they are still deciding whether the photographs seen by Mr Bush and others not yet published in the media should be released publicly.
With new pictures surfacing almost every day - the latest showing soldiers with dogs surrounding a naked prisoner - efforts to draw a line under the scandal appear to have failed.
Mr Bush pledged that any US soldiers who abused prisoners would be brought to justice.
"The conduct that has come to light is an insult to the Iraqi people and is an affront to the most basic standards of morality and decency," he said.
The president also praised the more than 200,000 US military personnel who had served in Iraq since the conflict began last year.
"I know how painful it is to see a small number dishonour the honourable cause in which so many are sacrificing," he said.
The BBC's Justin Webb in Washington says Mr Bush was trying to reassure US troops, and at the same time end suggestions that Mr Rumsfeld should resign.
Calls for him to leave have been made by opposition politicians and various newspapers, including the Army Times which published an editorial in effect calling on Mr Rumsfeld to be sacked.
The private newspaper, widely circulated at military bases, says Mr Rumsfeld and his top general, Richard Myers, should be held accountable.
"On the battlefield, Myers' and Rumsfeld's errors would be called a lack of situational awareness - a failure that amounts to professional negligence," the newspaper says.
A confidential report by the International Committee of the Red Cross (ICRC) has said the mistreatment of Iraqi prisoners in US custody is not limited to isolated cases, but forms part of a systematic pattern.
A spokesman said the ICRC had been warning the US about such cases for more than a year.
8,000 prisoners held in 14 separate jails
Three main prisons - Abu Ghraib and Camp Cropper in west Baghdad; Camp Bucca, near Umm Qasr - hold inmates for extended periods
Almost all inmates are "security internees" - suspected of posing a threat to the coalition
But the organisation's strict policy of confidentiality meant it could not go into details publicly about the warnings.
Friday's Wall Street Journal newspaper quoted the ICRC's 24-page report that alleges, among other things, that prisoners were kept naked in cells, in darkness and without facilities.
Top Democrats have pinned the blame for much of the scandal on President Bush.
"There's more than a systemic failure - there's a failure of leadership that goes right to the top," former Nato commander and one-time presidential hopeful Wesley Clark told NBC television.
UK minister pressured
UK Prime Minister Tony Blair has apologised for any cases of mistreatment of Iraqi prisoners by British soldiers.
But on Monday he told reporters that it was only in the last few days that his government had been made aware of specific allegations of abuse - and that was when pictures of alleged abuse appeared in the press.
In a statement to MPs on Monday, the UK Defence Secretary Geoff Hoon apologised "unreservedly" to any Iraqis who had been mistreated.
Mr Hoon said the ICRC report, which was given to coalition officials, had not been passed to ministers until "very recently" because its concerns had been addressed.
He said decisions on whether to prosecute British troops over alleged abuse of Iraqis were pending in two cases.