North Korea just detained an American professor

North Korea detained a U.S. citizen on Saturday while attempting to leave the capital city Pyongyang, for unknown reasons.

According to CNN, Kim Jong, an american professor at Pyongyang University of Science and Technology, was at the airport preparing to travel with his with wife to China when he was detained by Korean authorities.

Korean officials have not yet offered an explanation for apprehending Jong or any idea of how long he will be detained. Martina Aberg, deputy chief of mission for the Embassy of Sweden notified the U.S. on Saturday and offered a statement to CNN.

“He was prevented from getting on the flight out of Pyongyang,” said Aberg. “We don’t comment further than this.”

Jong is one of three detainees that are presently being imprisoned¬†by North Korea while attempting to leave from Pyongyang’s airport, with each previous case resulting in harsh punishments being passed down.

Otto Warmbier, a university of Virginia student, was detained last year in January for allegedly removing a political sign from a hotel wall, consequently, he was sentenced to 15 years.

Kim Dong Chul, a naturalized U.S. citizen, was arrested in October 2015 on espionage charges and was sentenced to 10 years.