At least 26 prisoners have died in American custody in Iraq and Afghanistan since 2002 in what Army and Navy investigators have concluded or suspect were acts of criminal homicide, according to military officials.
The number of confirmed or suspected cases is much higher than any accounting the military has previously reported. A Pentagon report sent to Congress last week cited only six prisoner deaths caused by abuse, but that partial tally was limited to what the author, Vice Adm. Albert T. Church III of the Navy, called ''closed, substantiated abuse cases'' as of last September.
The new figure of 26 was provided by the Army and Navy this week after repeated inquiries. In 18 cases reviewed by the Army and Navy, investigators have now closed their inquiries and have recommended them for prosecution or referred them to other agencies for action, Army and Navy officials said. Eight cases are still under investigation but are listed by the Army as confirmed or suspected criminal homicides, the officials said.
Only one of the deaths occurred at the Abu Ghraib prison in Iraq, officials said, showing how broadly the most violent abuses extended beyond those prison walls and contradicting early impressions that the wrongdoing was confined to a handful of members of the military police on the prison's night shift.
Among the cases are at least four involving Central Intelligence Agency employees that are being reviewed by the Justice Department for possible prosecution. They include a killing in Afghanistan in June 2003 for which David Passaro, a contract worker for the C.I.A., is now facing trial in federal court in North Carolina.
Human rights groups expressed dismay at the number of criminal homicides and renewed their call for a Sept. 11-style inquiry into detention operations and abuse in Iraq and Afghanistan. ''This number to me is quite astounding,'' said James D. Ross, senior legal adviser for Human Rights Watch in New York. ''This just reflects an overall failure to take seriously the abuses that have occurred.''
Pentagon and Army officials rebutted that accusation. Lawrence Di Rita, the chief Pentagon spokesman, said that he was not aware that the Defense Department had previously accounted publicly for criminal homicides among the detainee deaths in Afghanistan and Iraq, but insisted that military authorities were vigorously pursuing each case.
''I have not seen the numbers collected in the way you described them, but obviously one criminal homicide is one too many,'' said Mr. Di Rita, who noted that American forces had held more than 50,000 detainees in Iraq and Afghanistan over the past three years.
Army officials said the killings took place both inside and outside detention areas, including at the point of capture in often violent battlefield conditions. ''The Army will investigate every detainee death both inside and outside detention facilities,'' said Col. Joseph Curtin, a senior Army spokesman. ''Simply put, detainee abuse is not tolerated, and the Army will hold soldiers accountable. We are taking action to prosecute those suspected of abuse while taking steps now to train soldiers how to avoid such situations in the future.''
In his report last week, Admiral Church concluded that the abuse of prisoners in Iraq and Afghanistan had been the result primarily of a breakdown of discipline, not flawed policies or misguided direction from commanders or Pentagon officials. But he cautioned that his conclusions were ''based primarily on the information available to us as of Sept. 30, 2004,'' and added, ''Should additional information become available, our conclusions would have to be considered in light of that information.''
In addition to the criminal homicides, 11 cases involving prisoner deaths at the hands of American troops are now listed as justifiable homicides that should not be prosecuted, Army officials said. Those cases included killings caused by soldiers in suppressing prisoner riots in Iraq, they said. Other prisoners have died in captivity of natural causes, the military has found.