A U.S. national believed to be detained by North Korea after crossing the border from the South is believed to be a U.S. soldier, a U.S. official with knowledge of the situation told NBC News on Tuesday.
The source added that US officials were still gathering information on the “fluid” incident, which comes amid heightened tensions over North Korea’s nuclear program.
Earlier, the US-led UN command said a US national on an orientation tour had “crossed the military demarcation line into the Democratic People’s Republic of Korea without permission”.
“We believe he is currently being held in the DPRK and are working with our North Korean counterparts to resolve this incident,” he added. said in a tweet.
NBC News has contacted the White House for comment.
The anonymous person was on a tour of the Joint Security Area, which is part of the demilitarized zone between the two countries, according to the United Nations.
Tours of the region have been ongoing since the 1960s and are organized by private companies, while the UN organizes its own tours for its personnel.
The area lies just 30 miles north of Seoul, the South Korean capital, and has enormous historical significance as the place where the armistice to end the Korean War was signed in 1953.
The news comes as the USS Kentucky, a nuclear-powered submarine, arrived at the Busan naval base in South Korea on Tuesday.
“This stopover in Busan reflects the United States’ ironclad commitment to the Republic of Korea for our Extended Deterrence Guarantee,” U.S. Forces Korea said in a statement.
“This is a developing story. Please check for updates.
This article originally appeared on NBCNews.com