"One soldier was killed in a firefight. He was shot by insurgents," said Lieutenant-Colonel Michael Kurilla on Sunday.
The death raises the number of US soldiers killed in Iraq to 1372 since the March 2003 invasion, according to the latest figures from the Pentagon.
Twenty US soldiers have died in the volatile city of Mosul since 21 December when a bomber blew himself up in an army mess hall, killing 22 people, including 14 US troops.
Meanwhile on Sunday, six members of the Iraqi army were injured when a car bomb exploded at an army checkpoint in front of the Polish military headquarters in the southern city of Hilla, Aljazeera learned.
Separately, fighters attacked the al-Jazira police centre north of Ramadi city and confiscated equipment and weapons, Aljazeera learned. The fighters forced out all members of the attacked centre, threatening to kill them if they came back.