The call today from Louise Arbour, the UN high commissioner for human rights, follows reports of abuse of detainees at a secret facility in Baghdad.
Arbour welcomed an announcement that the Iraqi government will investigate. But she said an internal probe might not be enough, in the light of what she called "the apparently systemic nature and magnitude of the problem."
U.S. soldiers on 13 November found some 170 malnourished prisoners, some showing signs of abuse, at an Interior Ministry building.
(agencies)