The helicopter went down shortly after 11 a.m. (0200 GMT) for reasons that remain unclear, it said in a statement, Reuters reported.
The two crew members were evacuated to nearby hospitals, but were later pronounced dead.
The Army has suspended operations of all AH-1S helicopters following the accident and set up an emergency response team to investigate the cause of the crash.
The training involved practicing emergency landing procedures without shutting down the engine, according to the military.