A military statement said the helicopter was transporting personnel when it went down near the town of Rutbah, near the Jordanian border. The statement gave no further details.
The crash occurred as the U.S. military is attempting to secure Iraq before national and provincial elections on 30 January. U.S. officials expect insurgents to increase attacks in the run-up to the poll and on election day.
Election Commission spokesman Farid Ayar said yesterday that security will be tightened for the election but that there will be no general, nationwide curfew.
"All the people, they can move in the country [during the election], but there are special or certain places which are not allowed for vehicles to go there," Ayar said. "Only that there is no curfew or anything."
His statement came as Iraqi expatriates in 14 countries started to cast their ballots.