The US has said images broadcast on Australian TV showing the apparent abuse of Iraqi detainees by US soldiers should not have been released.
A US defence department official said the images could "further inflame and cause unnecessary violence".
The official said action had already been taken against US soldiers guilty of abuse at Baghdad's Abu Ghraib jail.
Australian TV has now aired previously unseen images of the apparent abuse of prisoners in Abu Ghraib in 2003.
The images on SBS TV are thought to be from the same source as those that caused an outcry around the world and led to several US troops being jailed.
The new images show "homicide, torture and sexual humiliation", SBS said.
The SBS' Mike Carey told the BBC the images screened by his network on Wednesday mark a "leap in seriousness" from previously released images of abuse at Abu Ghraib.
"We thought we had a responsibility first and foremost once we had obtained these photographs to broadcast them," he said.
A US state department legal adviser said the government felt it was better for the photos not to be released.
John Bellinger said this was "not because there was anything to hide" - but rather "because we felt it was an invasion of the privacy of the people in the pictures".
He said the images, which show "conduct that is absolutely disgusting" were likely to "fan the flames around the world and cause more violence".
His view was echoed by Pentagon official Bryan Whitman, who added that several US soldiers had been prosecuted over past abuses.
"There have been more than 600 criminal investigations into allegations of detainee mistreatment, and there have been more than 200 people held accountable for misconduct," he said.
"In Abu Ghraib specifically, there have been more than 25 individuals - officer and enlisted - that have been held accountable for criminal acts and other failures."
A Pentagon official, speaking on condition of anonymity, has confirmed the images aired on Wednesday are authentic, the AFP news agency reports.
"There is nothing new here," the official reportedly said, adding that the images "have been previously investigated as part of the Abu Ghraib investigation".
The images are thought to be part of a group of more than 100 photographs and four videos taken at Abu Ghraib and later handed to the US army's Criminal Investigations Division.
In September, a New York judge ruled in favour of a request from the American Civil Liberties Union for the pictures to be released.
The judge rejected the government's arguments that publication could fuel anti-US feelings.
The SBS' Dateline programme, which broadcast the pictures, says the government is appealing against the decision.
The broadcast of the images comes at a time of increased tension between Muslim nations and the West over cartoons satirising the Prophet Muhammad.
Analysts say the reaction in the Muslim world may depend on how widely the images are shown. In Iraq, the emergence of the images come amid tension caused by the release of a video appearing to show UK troops beating Iraqi civilians.
An Iraqi teacher, Hanan Adeeb, told the Reuters news agency that the new pictures "reignited the long-running pain that started with the occupation of Iraq".
One of the videos broadcast on the Dateline programme appears to show prisoners being forced to masturbate for the camera.
Other video footage appears to show a prisoner hitting his head against a wall.
The channel said he was a mentally disturbed patient who became a plaything of guards who practised ways of restraining him.
Some photos are said to show corpses. There are also images of prisoners with body and head wounds.
Some of the pictures have now been re-broadcast on US networks and on Arab satellite channels al-Arabiya and al-Jazeera.