At around midday, some parts of the road north of the military demarcation line dividing the countries were blown up, the joint chiefs of staff said in a message sent to media.

South Korea’s military had ramped up surveillance and its readiness in response, it said. Seoul had warned on Monday that Pyongyang was getting ready to blow up the roads.

Tensions on the Korean peninsula have been increasing amid an escalating war of words after the North accused its rival of sending drones over the country’s capital Pyongyang.

North Korea on Friday said the drones had scattered a “huge number” of anti-North leaflets over the city, in what it called political and military provocation that could lead to armed conflict.

A spokesman for the South’s joint chiefs of staff declined on Monday to answer questions over whether the South Korean military or civilians had flown the alleged drones.

North Korean leader Kim Jong-un had overseen on Monday a meeting with defence and security officials to discuss how to respond to the “enemy’s serious provocation that violated the sovereignty of the DPRK”, state media KCNA reported, using the acronym for North Korea’s official name.