American who crossed North Korean border was a U.S. soldier, official confirms

The American who crossed the border from South Korea to North Korea without authorization Tuesday is a U.S. soldier, a U.S. official has confirmed to POLITICO.

The crossing and presumed detention of the American, who has not been named, was announced Tuesday morning in a tweet from American-led United Nations Command in the Korean Peninsula.

“A U.S. National on a JSA orientation tour crossed, without authorization, the Military Demarcation Line into the Democratic People’s Republic of Korea (DPRK),” U.N. Command tweeted Tuesday. “We believe he is currently in DPRK custody and are working with our KPA counterparts to resolve this incident.” U.N. and U.S. officials did not provide a reason for the soldier’s crossing.

The U.S. soldier’s crossing and presumed detention comes amid escalating tension between the U.S. and North Korea over North Korea’s continued missile launches in the direction of neighboring South Korea and Japan. It is unclear whether the incident is related to the arrival of the USS Kentucky, a nuclear-armed submarine with ballistic missile capabilities, in Busan, South Korea, earlier Tuesday.

American officials say the deployment of the submarine is part of its “extended deterrence” policy.

“This port visit to Busan reflects the United States’ ironclad commitment to the Republic of Korea for our extended deterrence guarantee, and complements the many exercises, training, operations, and the other military cooperation activities conducted by Strategic Forces to ensure they are available and ready to operate around the globe at any time,” U.S. Forces Korea said in a news release Tuesday.

North Korean officials warned the U.S. on Monday against “foolish” actions. Workers Party official Kim Yo Jong, the sister of North Korean leader Kim Jong Un, said through state media that North Korea had launched a “military offensive” in response to U.S. aggression.