At least 108 people have died in American custody in Iraq and Afghanistan, most of them violently, according to US government data.
About a quarter of those deaths have been investigated as possible abuse by US personnel. The figure, far higher than any previously disclosed, includes cases investigated by the US army, navy, CIA and justice department.
Some 65,000 prisoners have been taken during the US-led wars in Iraq and Afghanistan, although most have been freed. The US defence department has never provided comprehensive information on how many prisoners taken during the US wars in Iraq and Afghanistan have died, and the 108 figure is based on information supplied by army, navy and other government officials. It includes deaths attributed to natural causes.
To human rights groups, the deaths form a clear pattern. "Despite the military's own reports of deaths and abuses of detainees in US custody, it is astonishing that our government can still pretend that what is happening is the work of a few rogue soldiers," said American Civil Liberties Union executive director Anthony Romero.
"No one at the highest levels of our government has yet been held accountable for the torture and abuse, and that is unacceptable."
Pentagon officials have pointed to a number of military investigations which found that no policy condoned abuse. Defence department spokesman Lieutenant Colonel John Skinner said the military has taken steps to reduce the chance of violent uprisings at its prisons and the use of excessive force by soldiers, and also has improved the health care available to prisoners.
"The military has dramatically improved detention operations, everything from increased oversight and improved facilities to expanded training and the availability of state-of-the-art medical care," he said in a statement.
Of the prisoner deaths at least 26 have been investigated as murders involving the abuse of prisoners; at least 29 are attributed to suspected natural causes or accident; 22 two are blamed on an insurgent mortar attack on April 6, 2004, on Abu Ghraib prison in Iraq; and at least 20 are attributed to "justifiable homicide", where investigations found US troops used deadly force appropriately, primarily against rioting, escaping or threatening prisoners.
AP