North Korea has reportedly detained another American citizen.
The country's official news agency reported Sunday that Kim Hak-song was arrested on charges of committing "hostile acts."
If the arrest is confirmed, Kim would be the fourth American held by the country. In late April, another American was arrested at Pyongyang International Airport on similar charges.
Both men worked for the Pyongyang University of Science and Technology, but it's not clear if there's a connection between the arrests.
In 2016, North Korea sentenced Otto Warmbier, an American college student, to 15 years hard labor. And Kim Dong-chul was sentenced to 10 years hard labor on charges of spying.
The arrests come at a time of increased tension between North Korea and the U.S. North Korea continues to test missiles and the U.S. sent warships to the Korean Peninsula as a show of force last month.