The State Department is playing down discovery of another detention center in Iraq containing hundreds of prisoners in cramped quarters and the apparent abuse of some of them.

Department officials called for Iraqi officials to investigate the second known mistreatment of detainees in a center maintained by the Interior Ministry. But James Jeffrey, a seasoned American diplomat who assists Secretary of State Condoleezza Rice on Iraq policy, said Monday he did not think it would discourage Sunni Arabs from voting in legislative elections on Thursday.

"We are looking into this one in more detail to find out what went on there, why these people were being detained there, why they were not turned over to the ministry of Justice and whether and to what degree they may have been mishandled," Jeffrey said at the Foreign Press Center.

"It's still early in this case," he said, but added, "In this second camp there are some questions."

Discovery of the first detention center last month led to strong condemnation by the U.S. and to the assignment of Justice Department officials to help in a wider investigation.

Responding to reports of a second center, State Department spokesman Adam Ereli said abuse was contrary to Iraqi policy and that all facilities maintained by the government would be investigated with the help of the U.S. Justice Department and the FBI.

"Clearly, there is a problem in Iraq and clearly the Iraqis understand that and are working to address it," he said. "It's a process that will not be resolved overnight."

Ereli said he would not "prejudge" what the Iraqi investigation might turn up.

Sunni leaders disclosed the detention centers, where many of the prisoners were Sunnis. The Iraqi government is dominated by sometimes rival Shiites.

The Bush administration is hoping for a strong turnout by all groups in Iraq to vote on Thursday as evidence that democratic procedures are taking hold in Iraq under U.S. tutelage.