( CNN ) -- A North Korean soldier on guard duty at the border dividing the two Koreas defected , telling authorities who received him in the South that he killed his superiors before fleeing across the Military Demarcation Line . South Korean soldiers at their guard posts reported hearing gunfire before he crossed into the South shortly after noon local time , according to a news release from South Korea 's Joint Chiefs of Staff . Soldiers in the South took the defector in on their side of the border and brought him to a safe place for questioning then tightened security in the area . The North Korean said that `` while he was on guard duty , he killed his platoon and squad leaders and defected thereafter , '' the JCS said . Defections over land through the heavily armed and fortified Demilitarized Zone ( DMZ ) are rare , as most fleeing the communist North prefer the greater odds of success of crossing by sea . `` The last North Korean soldier who defected ( over land ) was in March 2010 , '' said a spokesman from the defense ministry in Seoul . But with his comrades dead and no longer capable of hindering him , it was easy for the soldier to flee south . `` The distance between the North Korean guard post and the South Korean guard post is 500 meters , '' the official said , who asked not to be named , because he is not authorized to speak with the media . 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 , over two-thirds of them women . The annual number of refugees has climbed steadily from less than 100 in the 1990s to more than 2,000 per year since 2006 . North Korea defector living with quarter of a century of guilt . North Korean defector stands for South Korean election . After escape from North Korea , artist turns from propaganda to pop art . From the archives : South Korea wo n't return 9 defectors from the North .
South Korean soldiers hear gunfire before the defector crosses . Hide Caption Defections over land via the heavily armed DMZ are rare . The number of refugees fleeing per year has climbed dramatically over the years .