Kim Sang-duk, a U.S. citizen and professor at the Yanbian University of Science and Technology (YUST) in Yanji, China, was detained in North Korea on Saturday at Pyongyang's Sunan airport, a source familiar with the case confirmed to NK News on Sunday.

Chan-Mo Park, current chancellor of the Pyongyang University of Science and Technology (PUST), said that Kim and his wife had been on his way back to China after teaching a class in International Finance and Management at the university.