South Korean authorities have recovered 15 landmines believed to have been swept across the inter-Korean border by monsoon floodwaters, raising fresh safety concerns for residents and visitors in one of the world's most heavily fortified frontier zones. All 15 mines were found along coastal areas of Ganghwa, an archipelago county in South Korea's northwest that sits at the mouth of the Han River estuary — a waterway bisected by the border between the two countries. Officials confirmed the devices were discovered between July 23 and August 3.
The Demilitarised Zone (DMZ), which has divided the Korean Peninsula since the 1950–53 Korean War ended in an armistice rather than a peace treaty, is considered one of the most densely mined areas on Earth. Military data cited by South Korean media estimates some 800,000 mines are buried in and around the zone — many dating to the war itself, though mine-laying has continued in more recent years. South Korea's military had already warned last month that heavy rainfall could wash explosives into rivers crossing the border, potentially causing serious harm downstream. County officials have said they cannot rule out the possibility that more mines may still arrive.
The danger is not abstract. In 2015, two South Korean soldiers patrolling the western DMZ were severely wounded, each losing limbs, after stepping on a North Korean mine. The incident triggered a sharp drop in tourism to the Ganghwa area, a concern now resurfacing among local residents. One resident noted that despite the summer heat, around 300 people still dig for clams by hand along the coastline, an activity he described as worrying given the renewed mine risk. Authorities sent alerts to residents in late July warning them to stay vigilant along coastal zones.
The flooding that likely dislodged the mines has also caused significant damage on the North Korean side of the border. Satellite imagery cited by specialist outlet NK Pro indicates that at least 380 single-storey homes at a large North Korean border military base — reportedly a key artillery command site — were swept away in late July following what appeared to be a dam collapse. North Korea's vulnerability to flooding is exacerbated by widespread deforestation, which has stripped hillsides of vegetation that would otherwise slow water runoff.
The landmine episode unfolds against a backdrop of cautious South Korean efforts to ease tensions with Pyongyang. Seoul recently announced plans to resume construction of the Gyeongwon railway line, a historic route that once connected what is now Seoul with the North Korean east-coast city of Wonsan, and which has long symbolised the possibility of reunification. The project, paused a decade ago amid deteriorating relations, is now being revived as part of a broader set of diplomatic gestures. North Korea has not responded to the announcement.