A US soldier was killed and twelve others wounded when their helicopter crashed in the US military's main airbase in Iraq, the military said in a statement.
The helicopter went down over joint base Balad, about 80 km north of Baghdad, on Sunday, the statement said. US officials were not immediately available to comment on the suspected cause of the crash.
Air crashes have become less common in Iraq now that the United States has fewer aircraft crossing the country's skies.
The last reported incident was on July 17, when a US State Department helicopter crashed near Baghdad, killing two crew members. In January, two US military aircraft came under enemy fire and crashed into each other, killing four soldiers.