According to the US occupation forces, another soldier was injured and taken to a military hospital where he was listed as being in a serious condition. There was no word on Iraqi casualties.
Both soldiers were part of the 1st Armoured Division.
The occupation military said it did not believe the attack was related to the bombings at Shia shrines in the capital and in Karbala, which left several dead and injured.
The latest death brings to 548 the number of US soldiers who have died since the United States invaded Iraq in March 2003.
Most of that number have died since US President George Bush declared an end to major combat on 1 May.