U.N. official denied access to Iraq prisons - Los Angeles Times

Nowak said U.S. officials told him that American-run prisons in Iraq were not subject to international human rights law because of the armed conflict, and as such were outside his area of responsibility.
Wasnt noncooperation with the UN the main formal reason boasted by the Bush Regime in order to attack Iraq ? What is the US hiding inside it's Iraq prisons ? Is Abu Ghraib just the tip of the iceberg ?