The US general who helped uncover the Iraqi prison abusem scandal, said Tuesday a breakdown of leadership led to the mistreatment but there was no evidence American soldiers were following orders.

Major General Antonio Taguba told a congressional committee there was a "failure in leadership, from the brigade commander on down."

"Lack of discipline, no training whatsoever, and no supervision," were the main causes, Taguba told lawmakers.

"Supervisory omission was rampant."

In his report on abuses at the Abu Ghraib prison, Taguba highlighted "numerous incidents of sadistic, blatant and wanton criminal abuses" against Iraqi prisoners.

His report, along with pictures of naked prisoners piled in sexually humiliating positions, have shaken the US occupation of Iraq and drawn widespread international criticism.

US lawmakers were set to see unpublished pictures of abuse Wednesday, when the Defence Department will bring photographs to a private viewing at Congress for three hours.

Senator John Warner, head of the Senate Armed Services Committee, said only lawmakers would be allowed to see the pictures, which will be returned to the Pentagon because they are evidence in a criminal case.

He did not say whether the images would be made public, joining dozens already published and broadcast in the festering scandal.

Seven soldiers have already been charged over the abuse, but Taguba said there was no sign the US guards were following orders.

"We did not find any evidence of a policy," Taguba said in sworn testimony to the Senate Armed Services Committee.

The abuse heightened concern about the welfare of US troops and civilians in the region, and those concerns appeared to have been borne out with the news that a US businessman was beheaded in Iraq - apparently in retaliation for the abuse of Iraqis.

US officials confirmed that the body of 26-year-old Nicholas Berg, a businessman from Pennsylvania who had gone to Iraq seeking contracts, was found over the weekend.

Major General Ronald Burgess, director for intelligence, for the US Joint Chiefs of Staff, told the Senate hearing that while no firm link had been detected yet between the beheading and the Iraq prisons furore, the US military is paying greater "attention" to a possible backlash in Iraq and Afghanistan since the abuse scandal erupted.

"We have been following the intelligence and there has been an uptick ... an increase, if you will, in some of the threat reporting," he said.

In his testimony, Taguba, 53, one of two Filipino-American generals in the US Army, said the abuse began from mid-to-late October and continued until January.

The top Democrat on the committee, Carl Levin, suggested that top military officials may have sanctioned the abuse as a way to extract information from detainees.

"The collars used on prisoners, the dogs and the cameras did not suddenly appear out of thin air," Levin said.

"These acts of abuse were not the spontaneous actions of lower ranking enlisted personnel who lacked the proper supervision.

"These attempts to extract information from prisoners by abusive and degrading methods were clearly planned and suggested by others," Levin said.

But Taguba said: "At the end of the day, a few soldiers and civilians conspired to abuse and conduct egregious acts of violence against detainees and other civilians outside the bounds of international law and the Geneva Convention." Lawmakers again expressed their disgust at the extent of the brutality.

"The mistreatment of prisoners represents an appalling and totally unacceptable breach of military regulations and conduct," Warner said.

"The damage done to the reputation and credibility of our nation and the armed forces has the potential to undermine substantial gains and the sacrifices by our forces and their families and those of our allies fighting with us in the cause of freedom," the Republican senator added.

Germany Foreign Minister Joschka Fischer, who is in Washington for talks, called on the US to restore its "moral leadership" of the world by carrying out a full investigation of the Iraqi prison abuse scandal.

Speaking after meeting US Secretary of State Colin Powell, Fischer said Germany had been "really shocked and deeply appalled" by the images from Abu Ghraib.

"We need the United States, we need the moral leadership of the US, it is important for the West, for all of us," Fischer told reporters.

Referring to the various investigations underway, Fischer added, "We are looking forward that this situation will lead to the restoration of the moral leadership of the US, this is crucial for all of us." - Sapa-AFP