Baghdad, Iraq ? The Iraqi government has promised to investigate detention facilities across the country to ensure prisoners are not tortured, the United States said Thursday, sharply warning Iraqi officials against allowing Shiite militias a role in the security services following allegations of torture of Sunni Arabs.

The Interior Minister, who is in charge of the facilities and security forces, said torture claims were exaggerated.

Sectarian rhetoric sharpened four days after U.S. troops found up to 173 malnourished detainees – some showing signs of torture – in an Interior Ministry building in the capital’s Jadriyah district. Most were believed to be Sunni Arabs, the main group in the insurgency.

A leader of a major Sunni party, Tariq al-Hashimi, told Iraq’s Sharqiyah television that his group had submitted 50 complaints of prisoner abuse to the government, “but we did not receive a timely response.”

Interior Minister Bayn Jabr, a Shiite, brushed aside the complaints, denied sectarian bias and claimed that “every time” al-Hashimi has differences with him “he exerts pressure on me through the U.S. Embassy.”

“I reject torture and I will punish those who perform torture,” Jabr said. “No one was beheaded, no one was killed” – a clear reference to the beheadings of foreign and Iraqi hostages by insurgents, including al-Qaida’s Iraq wing.

He also said “those who are supporting terrorism are making the exaggerations” about torture and that only seven detainees showed signs of abuse.

“They have described the Interior Minister’s office as a place of execution,” Jabr said. “Let him come to show me if there is an execution place in this shelter.”

But Voice of America reported on its Web site Thursday that Jabr’s remarks about the number of abused prisoners contradicted what it witnessed Monday night, when U.S. troops moved the men from the Interior Ministry detention center to the American-run Abu Ghraib prison for medical care.

At least a third of the detainees “appeared severely emaciated and many showed cuts and bruises on their faces, arms and legs,” Voice of America reported.

In a statement Thursday, the U.S. Embassy said Iraqi authorities had given assurances they will investigate the conditions of the detainees found Sunday night and “undertake measures to ensure that no Ministry of Interior detainees would be subject to abuse anywhere in Iraq.”

“Detainee abuse is not and will not be tolerated by either the Iraqi government” or by U.S.-led forces, the embassy said. It said the government agreed to a six-point plan for ensuring accountability for abuse claims, but did not give details.

“We have made clear to the Iraqi government that there must not be militia or sectarian control or direction of Iraqi security forces, facilities or ministries,” it added.