One Marine was killed and 21 others have been injured after an Osprey aircraft made a hard landing in Hawaii, the Marine Corps said Sunday. The aircraft experienced a "hard-landing mishap" during training at the Bellows Air Force Station on Oahu, the 15th Marine Expeditionary Unit said in a statement. Residents reported seeing thick black smoke rising from the training area. The 21 Marines who were injured have been taken to local hospitals. The cause of the incident was not immediately known.