Work on a railroad and highway across the 20 kilometer wide DMZ (Demilitarized Zone that separates north and south Korea) has been stalled because there are not enough specialized manpower and equipment available to remove landmines in the south Korean sector. Some one million mines are in the DMZ, and many were hastily planted during the war, leaving no record of where they are. So a corridor several kilometers wide (and ten kilometers long) most be thoroughly swept of any mines. South Korea is looking into acquiring more advanced mine clearing equipment from foreign nations. The North Koreans, who were always expected to attack across the DMZ, apparently have sufficient resources to quickly clear their  half of the corridor.