The military statement on Monday said Second Lieutenant Erick Anderson had been "charged with premeditated murder and conspiracy to commit premeditated murder".
The charges were only allegations and Anderson was presumed innocent until and unless proven guilty, it added.
Anderson is serving with Task Force Baghdad, the military said, adding that details of the incident related to the charges could not be disclosed because of an ongoing investigation.
The latest case comes close on the heels of another involving two US soldiers facing trial on charges of murdering a wounded Iraqi teenager.
Earlier, four US soldiers were charged with murder in connection with the suffocation of an Iraqi general during questioning in Iraq last year.
The US army said the Iraqi general was asphyxiated by chest compression and smothering.
A growing number of US soldiers have been hauled up on charges of murdering civilians and prisoners of war since the invasion of Iraq in March 2003.