Iraq's Defense Ministry says a military helicopter has crashed during a training exercise, killing all three crew members on board.

The statement says the Russian-made Mi-17 helicopter crashed Sunday morning in the central Wasit province. The cause of the accident was not immediately known. The ministry initially reported that seven crew members died.

The province is located about 100 miles (160 kilometers) southeast of Baghdad, far from the front lines of the war with the Islamic State group. U.S.-backed Iraqi forces have driven the extremists from nearly all the territory they once controlled, with some fighting still underway near the western border with Syria.