The situation in Iraqi prisons is particularly acute, the UN Assistance Mission to Iraq said in a report, released ahead of the transfer next year of possibly thousands of detainees from U.S. military control to Iraqi authorities.
Many detainees in Iraqi jails had been held for months or years without being charged, granted access to lawyers or even to a judge, the report said. Allegations of widespread torture and ill treatment were of particular concern.
"They need to be charged, they need to have access to legal counsel, and the cases need to be investigated," the head of the UN mission, Staffan de Mistura, said in a news conference.
Under a U.S.-Iraqi security pact that comes into force next year, the U.S. forces who invaded Iraq in 2003 to topple Saddam Hussein will have to hand over to Iraqi control more than 16,000 detainees currently held in U.S. camps.
Those facing Iraqi arrest warrants will likely end up in Iraqi prisons, while the rest will have to be freed.
The UN report also highlighted the targeted killings of journalists, teachers, doctors, judges, government officials, and minorities, such as Christians or Turkmen, as causes for concern.