Most North Koreans who want to defect to the south slip through the Chinese border, but this was not the case for the North Korean teen soldier who defected to the south by walking across the dreaded demilitarized zone.

According to a South Korean Defense Ministry official who refused to be named, the soldier went to a South Korean guard post in Gangwon at 8 a.m. Monday and communicated to the guards that he wanted to defect. The guards did not fire warning shots at him after he made his intention clear, NBC News reports.

"A North Korean man presumed to be a serviceperson defected to our side earlier this morning," the official said. "He crossed the border in Hwacheon, Gangwon Province, on foot, and expressed his will to defect," he added, according to Yonhap News Agency, a South Korean media outlet.

The North Korean soldier is now being held in custody. South Korea has not issued an official confirmation of the report.

The DMZ, which stretches 2.5 miles wide, is riddled with landmines and bordered by huge barbed wires. An official from the south said that in recent months, North Korea has been planting more landmines along the border to keep the soldiers from defecting to the south, according to Yonhap News Agency in an earlier report. The Chinese border is also being strengthened.

"Under the order of leader Kim Jong-un, the military has gone all-out to prevent soldiers from going AWOL across the North Korea-China border," the official said.

Although it is rare for defectors from the north to cross the border through the heavily guarded DMZ, this is not the first time it happened. In 2012, a soldier crossed over to the south without being detected. He reportedly knocked on the door of a South Korean barracks in Kangwon, causing the defense minister to issue a public apology for "a clear failure in security operations," according to CNN.

Hundreds of North Koreans defect to the south every year to flee poverty.