The United Nations High Commissioner for Human Rights, Louise Arbour, is calling for an international investigation into conditions of detention in Iraq. She says the recent discovery in an Interior Ministry building of detainees who appear to have been tortured point to widespread problems with the system of detention in the country.

The U.N.'s top Human Rights Official, Louise Arbour, says there's evidence that prisoner abuse in Iraq is widespread and systemic. She says the large number of detainees in the country is very worrisome. She says a report by her office and the U.N. Assistance Mission in Iraq shows the number of people detained continues to increase due to mass arrests carried out during security and military operations.

U.N. human rights spokesman, Jose Diaz, says the high commissioner is concerned that many people interned for lengthy periods for security reasons have no legal recourse.

"We have detainees who are still being held even after there have been judicial orders for their release," he said. "I think one of the biggest problems is that there is no adequate judicial oversight. So, all of these problems are going to have to be looked at comprehensively. I think a system-wide investigation with an international element will go a long way toward assuaging a lot of concern and having some public confidence in the results of such an inquiry."

Mr. Diaz says it is difficult to know how many people are detained in prisons under Iraqi control because many are being held in undisclosed locations.

Iraq's interior minister said Thursday abuse reports had been exaggerated, saying only seven detainees showed signs of abuse. He said those responsible will be held accountable.

Nearly 170 Iraqis discovered by American soldiers on Sunday were found in a secret police prison in central Baghdad. They reported the men were malnourished and had signs of having been tortured.

Mr. Diaz says the allegations are deeply disturbing and must be thoroughly investigated.

"I think there is a recognition by all that a purely national inquiry would not have the necessary public confidence to assuage these very serious concerns," he said. "It is very important not only that the investigation be objective and impartial, but that it is perceived by Iraqis from all quarters and from all persuasions that it is being objective and not favoring one side or another."

Virtually all the prisoners discovered in the Interior Ministry complex were Sunni Arabs. Their jailers were Shi'ites. Mr. Diaz calls this ethnic divide a potentially explosive mix and says it is hard to know what would happen if a probe into the treatment of the prisoners was not perceived to be fair and just.