The soldier was part of a group taking a tour of the Joint Security Area – the border village in the demilitarized zone separating the two Koreas, which is heavily guarded by soldiers from both sides.
The UN Command in a statement said: “A US National on a JSA (Joint Security Area) orientation tour crossed, without authorisation, the Military Demarcation Line into the Democratic People’s Republic of Korea (DPRK).”
The American national is believed to be currently in custody in the North, the authorities said, adding that “we are working with KPA (North Korean army) counterparts to resolve this incident”.
US officials later confirmed that the individual was a US service member and that he was thought to be in the custody of North Korean forces.
A US official told CBS News that the service member was being escorted back to the US following disciplinary issues but was able to return and join the border tour after going through airport security.
According to the local press, a foreign national crossed the border at 3.27pm local time – 2.27am ET.
An individual who said they witnessed what took place and was taking part in the tour along with the US soldier told CBS News that they had visited one of the buildings in the area when “this man gives out a loud ‘ha ha ha,’ and just runs in between some buildings”.
“I thought it was a bad joke at first, but when he didn’t come back, I realised it wasn’t a joke, and then everybody reacted and things got crazy,” they told the outlet.
The witness told the network that no North Korean soldiers could be seen where the man ran, adding that they had been told that there hadn’t been any present since the pandemic as North Korea attempted to fully close its borders.
The witness said that after the man had crossed the border, the tour group was taken to Freedom House to give statements and then to be taken to their bus.
“I’m telling you this because it actually hit me quite hard,” the witness told CBS News. “It was on the way back in the bus, and we got to one of the checkpoints … Someone said we were 43 going in and 42 coming back.”
An anonymous official told The Washington Post that “This was a deliberate decision on part of the service member to cross”.
Colonel Isaac Taylor told Reuters that “We’re still doing some research into this, and everything that happened”.
The Independent has reached out to the US Army for comment.
The DMZ, one of the most fortified places in the world, is filled with landmines, surrounded by electric and barbed wire fencing and surveillance cameras.
While there are very few cases of Americans or South Koreans defecting to the North, more than 30,000 North Koreans are believed to have crossed the border to the South since the 1950s.
Washington has banned American nationals from entering North Korea “due to the continuing serious risk of arrest and long-term detention of US nationals”.
“The US government is unable to provide emergency services to US citizens in North Korea as it does not have diplomatic or consular relations with North Korea,” the US travel advisory for North Korea reads.
The ban was implemented after American college student Otto Warmbier was detained by the North while on a tour of the country in 2015. He died in 2017, days after he was released from prison and returned to the US in a coma.
Panmunjom, located inside the 248km-long demilitarised zone, was created at the close of the Korean War in 1953. The area has been a venue for numerous talks and is a popular tourist spot.
In November 2017, North Korean soldiers fired 40 rounds as one of their colleagues raced toward the South. The soldier was hit five times and later rescued from beneath a pile of leaves on the southern side of Panmunjom. He is now in South Korea.
Former US president Donald Trump met his North Korean counterpart Kim Jong-un in the DMZ in June 2019.
The arrest comes amid heightened tensions between the US and the North as Pyongyang rushes to fulfill its nuclear aspirations.
Washington deployed a nuclear-armed submarine to its ally, South Korea, for the first time in 40 years as officials from both countries met in Seoul to discuss strengthening their nations’ deterrence capabilities against the North.
Ohio-class USS Kentucky submarine arrived at the port of Busan on Tuesday afternoon, the South’s defence ministry said. It is the first visit by a US nuclear-armed submarine to the South since the 1980s, it added.
Periodic visits by US nuclear ballistic missile-capable submarines to the South were one of the agreements reached by both countries in April. They also agreed to establish a bilateral Nuclear Consultative Group and expand military exercises.