U.S. and Iraqi forces raided the Health Ministry in Baghdad and detained the deputy minister on Thursday, a ministry spokesman said.
"Hakim al-Zamili, a deputy minister, was arrested by joint U.S. and Iraqi forces who raided the ministry building for unknown reasons," the spokesman said.
Al-Zamili is a senior member of the Sadr movement loyal to radical cleric Muqtada al-Sadr. The movement is part of the Shiite Alliance which leads the government.
There was no immediate comment from the U.S. military. The raid came one day after the U.S. military said that a new Baghdad security plan has begun.