U.S. forces have been carrying out a major operation near the northern city of Kirkuk.
Iraqi officials told reporters the target of the operation in the town of Hawijah was Saddam Hussein's deputy, Izzat Ibrahim al-Duri. But a U.S. officer, Major Doug Vincent, has denied some reports that Mr. al-Douri was captured.
Mr. al-Douri is the highest ranking member of the former regime -- after Saddam Hussein himself -- still at large. The US military believes he may be behind recent deadly attacks on coalition forces and it has offered a 10-million-dollar reward for information leading to his capture or death.
Last week, U.S. troops captured Mr. al-Douri's wife and daughter, as well as a number of his supporters, during a raid in the town of Samarra. U.S. Central Command said at the time there was no indication that Mr. al-Douri was in the vicinity.
Also Tuesday, a U.S. soldier was killed by a roadside bomb south of Samarra, where there was a major clash Sunday between coalition troops and insurgents.