International: In a significant move, North Korea has blown up sections of an inter-Korean road on its side of the heavily militarised border between the two Koreas, according to South Korea's Joint Chiefs of Staff on Tuesday, marking a major escalation in tensions between the two countries. This came after North Korea accused the South of sending drones over its capital city of Pyongyang and warned of a "horrible disaster".

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. The explosions came a day after North Korean leader Kim Jong Un called a meeting with his top military and security officials and described the alleged drone intrusion as a "serious provocation" by the "enemy".

South Korea had warned on Monday that the North was getting ready to blow up the roads and had ramped up surveillance and its readiness in response to the explosions. 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.

Kim Jong Un decries 'violation of sovereignty'

In the Monday meeting with North Korean officials, Kim Jong Un discussed how to respond to the "enemy's serious provocation that violated the sovereignty of the DPRK" and laid out unspecified tasks related to “immediate military action” and the operation of his “war deterrent. North Korea had also put frontline artillery and other army units on standby to launch strikes on South Korea in case of another drone intrusion.

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. 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.

Last week, North Korea said it would permanently block its border with South Korea and build front-line defense structures to cope with “confrontational hysteria” by South Korean and US forces. South Korean officials said North Korea had already been adding anti-tank barriers and laying mines along the border since earlier this year.

Kim's powerful sister issues dire warning

In a fiery statement as usual, Kim Jong Un's powerful sister Kim Yo Jong warned South Korea of a "horrible disaster" if the country flies drones over Pyongyang. Kim said the blame lies with the South Korean military if it failed to identify drones sent by a non-governmental organisation crossing the border.

"The most childish Republic of Korea which is utterly ignorant is resorting to a stereotyped method to suit to its inborn nature in order to evade the responsibility for the recent drone intrusion case... It is a miscalculation if the military thinks that it can easily pass through the crucial infringement upon the sovereignty of our state, even with impunity though the military impudently asserts that they did not do it, and avoid the eyes of concern of the international community," she was quoted as saying by state-run KCNA.

North Korea has been floating thousands of balloons with trash attached into the South since May, exacerbating tensions between the two countries. Pyongyang says they are a response to some activists and North Korean defectors in South Korea who fly balloons into the North carrying aid parcels and leaflets criticising leader Kim Jong Un.

Earlier,  Kim Jong Un threatened to use nuclear weapons to 'destroy' its arch-rival South Korea permanently if its sovereignty was breached, according to state-run media, after the South's leader threatened to end Kim's regime if he attempted to use nuclear weapons. The exchange of such heated remarks, while nothing new, came amid heightened tensions over Pyongyang's continuation of missile tests and disclosure of a nuclear facility.