North Korea has detained a U.S. citizen, according to South Korean media.
The chancellor of Pyongyang University of Science and Technology told the AP and other outlets that the man detained is Tony Kim, also known by his Korean name, Kim Sang-duk. He reportedly worked as a professor at the university.
He was reportedly arrested over the weekend at the Pyongyang International Airport after spending roughly a month working on aid for the country.
North Korea has a reputation for using foreign prisoners as diplomatic pawns. Out of a handful of Americans arrested there in recent years, two are still known to be imprisoned.
One is Otto Warmbier, a college student who was arrested in 2016 for stealing a political sign and sentenced to 15 years hard labor.
The other is Kim Dong-chul, a naturalized U.S. citizen born in South Korea. He was sentenced to 10 years for espionage and other charges.
Relations between the U.S. and North Korea have never been great, but this latest arrest comes at a time of especially increased tension between the two countries.