The aircraft, which is believed to be a fighter jet, crashed in Chilgok county, the Yonhap news agency reported.
No further details have been provided so far.
The agency also quotes eyewitnesses from the nearest country club and police station, who said the plane fell in the mountains and that several explosions were heard.
There are no data on the victims yet.
The police and firemen are directed to the crash site of the aircraft.
There has been no information so far on whether it as a South Korean plane or it belonged to the US Air Force, which has military presence in the country.
More about: South-Korea
