South Korea claims North Korea is preparing to blow up border roads

North Korea is preparing to blow up roads that cross the heavily militarised border with South Korea, Seoul has said.

Troops from North Korea were spotted working on the roads, the South's military spokesperson said, with preparations to detonate as early as Monday.

"They have installed screens on the road and are working behind those screens, preparing to blow up the roads," Lee Sung Joon, spokesperson of South Korea's joint chiefs of staff, told a briefing.

Destroying the roads would be in line with Kim Jong Un's push to cut off ties with South Korea and formally cement it as the North's principal enemy.

It comes after the North accused the South of launching drones over its capital three times this month in order to drop propaganda leaflets.

The country's military warned of a "horrible disaster" if the drones were located again and said it has put eight-armed artillery units at the border "on standby to open fire".

According to experts, it is highly unlikely for the North to launch full-scale, pre-emptive attacks as its military is outmatched by the combined US and South Korean forces.

South Korea has refused to confirm whether it sent drones, but warned it would punish North Korea if the safety of its citizens is threatened.

Officials in the South claim the North has been adding anti-tank barriers, planting mines and reinforcing roads on its side of the border since earlier this year in a likely attempt to boost its frontline security and prevent soldiers and citizens from defecting.

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Tension between the two is at its highest point in years - with North Korea continuing a run of weapons tests and South Korea expanding military drills alongside the US.

In January, Kim Jong Un ordered the revision of North Korea's constitution to remove the goal of a peaceful Korean unification, and formally designate South Korea as the country's "invariable principal enemy".

This was seen as a break from his predecessor's long-term goal of achieving a unified Korea on the North's terms.

(c) Sky News 2024: South Korea claims North Korea is preparing to blow up border roads