The Pentagon is investigating an allegation that a U.S. soldier raped an Iraqi female prisoner while she was in U.S. military custody, Pentagon spokesman Bryan Whitman said Tuesday.

The allegation has not yet been substantiated, he said. He gave no details.

Another rape allegation against a U.S. soldier by an Iraqi woman was dismissed for lack of evidence, Whitman said.

They are the only two rape allegations that have been made against U.S. troops by Iraqi women, the spokesman said.

During testimony last week on Capitol Hill, Defense Secretary Donald H. Rumsfeld and Gen. Richard Myers, chairman of the Joint Chiefs of Staff, were pressed for information about rape allegations against U.S. forces in Iraq. Rumsfeld promised to look into the matter and report his findings.