‘North Korean landmines could float into South Korea’

South Korea warns of North Korean landmines being swept into its territory by flooding, raising security concerns.

North Korean landmines could be swept into South Korea by flooding, South Korea's military warned on July 17, after the North has recently placed tens of thousands of additional deadly explosives along the rivals' heavily fortified border.

North Korea's minelaying is part of construction at the border that's been going on since April, which also includes adding anti-tank barriers and reinforcing roads. South Korea officials believe North Korea aims to boost its frontline security posture and prevent its soldiers and citizens from defecting to South Korea.

South Korea's Joint Chiefs of Staff told local reporters that flooding caused by summer rainfall could wash the mines over the border, adding that North Korea might also deliberately float mines downriver as a provocation.

The contents of the briefing were shared with AP.

Concerns about possible North Korean provocation have deepened after Kim Yo Jong, the powerful sister of North Korean leader Kim Jong Un, threatened new countermeasures Tuesday against South Korean civilian activists' efforts to drop leaflets over the north by balloon. North Korea has earlier responded by flying trash-carrying balloons toward South Korea, which have not caused major damage.

The Joint Chiefs of Staff said in a statement that North Korea's military has suffered “many casualties" from about 10 mine explosions and heat exposure during the intense border works.

An estimated 2 million mines are believed to be strewn in and around Koreas' 248 kilometre (154 miles)- long and 4 kilometres (2.5 miles)-wide land border. Experts say both Koreas have poorly managed their mines and don't know exactly how many they have planted or where they are.