Iraq is investigating allegations of abuse after more than 160 prisoners were found locked in an Interior Ministry bunker in Baghdad.
The detainees were discovered on Sunday night during a raid by US troops who were searching for a missing teenage boy. Many of them were beaten and malnourished and some had apparently been tortured.
Deputy Interior Minister Hussein Kamal
The prisoners were found in an underground cell near an Interior Ministry compound in Jadriya, a central Baghdad neighbourhood.
"There were 161 detainees in all and they were being treated in an inappropriate way . . . they were being abused," a deputy interior minister, Hussein Kamal, said.
"I've never seen such a situation like this during the past two years in Baghdad, this is the worst," he told CNN.
"I saw signs of physical abuse by brutal beating, one or two detainees were paralysed and some had their skin peeled off various parts of their bodies."
"This is totally unacceptable treatment and it is denounced by the minister and everyone in Iraq," Mr Kamal told reporters.
The minister said the detainees had all originally been detained with arrest warrants. They had now been moved to another facility where they were receiving medical assistance.
It was not clear why they had been arrested in the first place. Most detainees are suspected of supporting the Sunni Arab insurgency against the Shia- and Kurdish-led government.
Iraq's Sunni Arab minority has accused militias linked to the Shia-run Interior Ministry and Shia political parties of rounding up Sunnis in raids and holding them without charge. The government has denied the accusations.