United States army medics have been accused of being complicit in the abuse of Iraqi inmates at Abu Ghraib prison, outside Baghdad.
The US army is investigating abuse at Abu Ghraib prison
Writing in the medical journal The Lancet, Professor Steven Miles of the University of Minnesota says some collaborated with abusive guards.
The academic, who tried to become a US Democrat senator in 2000, has called for an inquiry.
However, the US Pentagon has dismissed the claims.
In a statement, it said it was investigating all aspects of detainee operations but had found no evidence that medical personnel were involved.
Reports of abuse at the US-run Abu Ghraib prison, 20km west of Baghdad, first came to light at the end of April.
Photographs showing naked Iraqi detainees being humiliated and maltreated sparked anger across the world.
They followed allegations of abuse against prisoners in Afghanistan and the US detention centre at Guantanamo Bay.
"Confirmed or reliably reported abuses of detainees in Iraq and Afghanistan include beatings, burns, shocks, bodily suspensions, asphyxia, threats against detainees and their relatives, sexual humiliation, isolation, prolonged hooding and shackling, and exposure to heat, cold and loud noise," said Professor Miles.
He said there was evidence that some medics had played a part.
"Government documents show that the US military medical system failed to protect detainees' human rights, sometimes collaborated with interrogators or abusive guards, and failed to properly report injuries or deaths caused by beatings," he said.
"In one example, soldiers tied a beaten detainee at the top of his cell door and gagged him.
"The death certificate indicated that he died of 'natural causes...during his sleep'. After news media coverage, the Pentagon revised the certificate to say that the death was a 'homicide'."
Professor Miles called for this and other incidents to be investigated.
"Although the US Armed Forces's medical services are mainly staffed by humane and skilled personnel, the described offences do not merely fall short of medical ideals; some constitute grave breaches of international or US law," he said.
In an accompanying editorial, The Lancet called on US army medics to come clean.
"Guidelines and codes of practice state that doctors, even in military forces, must first and foremost be concerned about their patients and bound by principles of medical ethics," it said.
"Health care workers should now break their silence. Those who were involved in or witnessed ill-treatment need to give a full and accurate account of events at Abu Ghraib and Guantanamo Bay."
However, a spokesman for the US Pentagon rejected the claims.
"Miles' article is based on carefully selected media reports and excerpted Hill testimony and not first hand investigative work or accounts.
"The Department of Defense takes strong exception to these allegations and his wholesale indictment of the medical care rendered by US personnel to prisoners and detainees.
"Miles' article paints an inaccurate picture of how medical personnel performed their duties and upheld their obligations."
He added: "Although investigations have not been completed, we have no evidence that military medical personnel collaborated with abusive behaviour by interrogators or guards, or condoned any abusive behaviours. There is no evidence that final death certificates were falsified."