Iraqi officials say U.S. forces detained five people in a pre-dawn raid on the Iranian consulate in the northern city of Irbil.
The U.S. military confirmed a raid Thursday in Irbil but says the targeted building was not a consulate or government office. The military also says the operation netted six suspects.
A Pentagon spokesman says those detained are suspected of being involved in efforts to kill Iraqi citizens and coalition troops. He did not reveal their nationalities.
The regional Kurdish government of northern Iraq condemned the detentions and called for the release of the suspects.
Iranian Foreign Ministry official spokesman Mohammad Ali Hosseini is quoted in Iranian media as condemning the raid and saying it was against diplomatic norms.
The United States accuses Iran of providing material support to the insurgents, and allowing terrorists to use Iranian territory to cross in and out of Iraq.
Last month, American forces in Baghdad detained several Iranians suspected of planning attacks against troops in Iraq.
In a television interview Thursday, U.S. Secretary of State Condoleeza Rice referred to the December detentions and said those individuals had been expelled from Iraq.
Separately, the U.S. military said coalition forces killed eight suspected terrorists and detained seven others in recent raids in the Tarmiyah area, north of Baghdad.
The military also said an Iraqi soldier was killed in Anbar province Wednesday by a bomb being carried by a 13-year-old boy. The military says it is not known if the boy knew he was carrying an explosive device.
In other violence in Iraq, five off-duty police were killed in an ambush in Baghdad, and a professor was gunned down in the northern city of Mosul.
Some information for this report was provided by AFP, AP and Reuters.