SEOUL, South Korea (AP) — South Korea said North Korea blew up the northern parts of inter-Korean roads no longer in use on Tuesday, as the rivals are locked in rising animosities over North Korea’s claim that South Korea flew drones over its capital, Pyongyang.

South Korea’s Joint Chiefs of Staff said in a brief statement that North Korea blew up parts of the roads on Tuesday.

It said South Korea’s military is bolstering its readiness but gave no further details.

Destroying the roads would be in line with leader Kim Jong Un’s push to cut off ties with South Korea, formally cement it as his country’s principal enemy and abandon the North’s decades-long objective to seek a peaceful Korean unification.

North Korea’s state media said earlier Tuesday that Kim convened a security meeting on Monday and ordered important steps related to the operation of the country’s war deterrent in response to the alleged drone flights by South Korea.

During the previous era of inter-Korean detente in the 2000s, the two Koreas reconnected two road routes and two rail tracks across their heavily fortified border. But their operations later were suspended one by one as the Koreas wrangled over North Korea’s nuclear program and other issues.

The Associated Press