The State Department is investigating "serious and credible" reports that minorities in Kurdish-held areas of northern Iraq have been wrongly arrested and detained, spokesman Sean McCormack (search) said Wednesday.

The U.S. government has conveyed its insistence on the rule of law and its support for minority rights to Iraqi security authorities, McCormack said.

The Washington Post reported Wednesday that police and security forces led by Kurdish political parties, and backed by the U.S. military, abducted hundreds of minority Arabs and Turkmens in Kurdish areas. The newspaper said the abductions began more than a year ago and accelerated after the Jan. 30 election.

McCormack declined to identify the Kurds (search) as being responsible for the abductions, or the Turkmens (search) and Arabs as victims. "I don't want to single out anybody," the spokesman said.

At the same time, he denied U.S. forces had participated in joint raids or played any role in the detentions. "Our coalition forces, according to every report that I have, not only were not involved in these activities but, in fact, raised their concerns" about the reported abuses, McCormack said.

Making clear the State Department had its own information apart from the Post report, McCormack said "we have had serious and credible information about allegations of extrajudicial conduct, both arrests and detentions" and "these reports are of very serious concern to us."

"Our reporting from the field did outline what we believe are serious and credible allegations of this activity," McCormack said at the department's daily press briefing.

Kurdish political parties hope to gain control of Kirkuk and its oil reserves. The former President Saddam Hussein forced thousands of Kurds out of the city and replaced them with Arabs. The Turkmens, meanwhile, have a special attachment to Kirkuk because it was under Turkmen control during the Ottoman Empire.

The area, among others, has been struck by violent opposition to the new Iraqi government and to the U.S.-led military coalition in Iraq.