SEOUL, South Korea — A North Korean soldier defected to South Korea on Saturday morning, fleeing across the countries’ heavily armed land border, officials said.

South Korean soldiers guided the North Korean to safety after they found him walking across the eastern sector of the Demilitarized Zone, the buffer zone separating the Koreas, the South Korean military said in a brief statement.

South Korean officials planned to debrief him to try to determine his motive for defecting, the military said. There was no unusual movement from the North Korean Army at the time the soldier crossed, it said.

Although more than 32,000 North Koreans have defected to South Korea, most have done so through China, eventually making their way to a South Korean embassy in another country. It is rare for defectors to cross the Demilitarized Zone, which is fortified by layers of barbed-wire fences, minefields and armed sentries on both sides.