A U.S. F-16 fighter jet crashed in South Korea on Monday while on a routine training flight and the pilot was rescued after ejecting when the aircraft experienced an "in-flight emergency," the U.S. Air Force unit stationed in the country said.

The pilot was rescued by the South Korean coast guard in the Yellow Sea and returned to the Kunsan Air Base, the 8th Fighter Wing said in a statement.

The cause of the emergency was being investigated, it said.

The unit commander, Colonel Matthew Gaetke, said he was grateful for the pilot's recovery and that he was in good condition, the statement said.