The UN says the US national crossed during an orientation tour of the Joint Security Area (JSA) between North Korea and South Korea.
It’s still not clear who the American is or why they crossed, but tours such as this are common.
They take place specifically in Panmunjom, which has historically been the only place along the border where troops from the two Koreas face each other.
It is where the Korean Armistice Agreement of 1953 was signed, effectively ending the Korean War.
The village is also used as a meeting point. It is where former US President Donald Trump stepped foot into North Korea as he met Kim Jong-un in 2019.
A professor in South Korea tells the AFP news agency that the area is likely where the US national crossed.
“It’s the only location one could attempt such a move out of the whole JSA tour,” Choi Gi-il, a professor of military studies at Sangji University, said.
