The man crossed into South Korea late on Wednesday and was spotted moving south along the Imjin River about 11:38 p.m., South Korea’s Joint Chiefs of Staff said.

“The man is an active-duty soldier, and he expressed his desire to defect to the South. Related procedures are underway,” a Joint Chiefs of Staff official said, according to South Korea’s semiofficial Yonhap news agency.

About 1,100 North Korean defectors arrived in South Korea last year, according to the South’s Unification Ministry.

But it is relatively rare for North Koreans to attempt to cross directly to the South. Doing so involves traversing the demilitarized zone, a heavily defended strip of no man’s land running across the peninsula that is dotted with military guard posts, land mines, barbed wire and other barriers.