The MH-53 helicopter from the U.S. Navy made the emergency landing on a rice paddy in Pohang, 374 kilometers southeast of Seoul, at 12:30 p.m. while performing flight training, according to the southern branch of the Pohang Fire Station.
After hitting the ground, a fire that started on the rotor destroyed the helicopter before being putting out by firefighters sent to the scene.
All twelve U.S. solders aboard the helicopter quickly evacuated and no injuries or further damage was reported, the fire station said.
"The fire began at the propeller following the emergency landing and moved into the fuel tank and the main body," a fire station official said. "No damage was reported except the destruction of the aircraft."
The cause of the unexpected landing is not immediately known. The helicopter was delivering soldiers and military supplies to a Navy unit.
Police and the U.S. military are jointly studying the cause of the accident.