The North Korean People's Army's General Staff said Monday the move would assist in "fortifying the front line and further strengthening the military border with South Korea."
Skepticism over North Korea's intentions mounts.
South Korea said the move "will contribute substantially to the alleviation of military tensions and the building of trust between the two Koreas."
Could this be the beginning of a reunited Korea?
A South Korean law allows the country to deport foreigners if they pose a threat to security or public interest.
It's the first defection of this kind in a decade.
"We want it to be the peace Games," the organizing committee chief said.