More than 24,000 refugees have entered the South from the North since the country 's division , according to the Ministry of Unification in Seoul . The South Korea - North Korea border is considered the most heavily militarized in the world . the past two months , a South Korean soldier crossed it undetected . He is one of three defectors in the past two months , a lawmaker says . The North Korean defense minister apologizes for the security failure .
The South Korea - North Korea border is considered the most heavily militarized in the world . the past two months , a South Korean soldier crossed it undetected . He is one of three defectors in the past two months , a lawmaker says . The North Korean defense minister apologizes for the security failure .