South Korea's military said it fired warning shots near its heavily fortified border on Tuesday after North Korean forces reportedly destroyed roads along the border.

It comes days after the North vowed to permanently seal off its southern border.

South Korea's Joint Chiefs of Staff said Pyongyang "conducted an explosive operation aimed at blocking the connection roads" on Tuesday.

As a response, the South Korean military said it "conducted counter-fire in areas south of the military demarcation line."

South Korea's military provided a video that showed a cloud of white and gray smoke emerging from an explosion at a road near the border town of Kaesong. Another video showed smoke emerging from a coastal road near the Korea's eastern border.

South Korea's military shared footage of explosions along inter-Korean roads. (Deutsche Welle)

Although the roads and railways connecting the two countries have long been shut down, North Korean state media reported that the new measures were aimed at safeguarding national security and preventing war.

Earlier this year, North Korean leader Kim Jong Un declared the South his country's "principal enemy" and since then, the regime has laid fresh mines, erected anti-tank barriers, and deployed missiles capable of carrying nuclear warheads along the already heavily fortified border.

Kim convenes meetings over drones

On Saturday, North Korea accused Seoul of using drones to drop anti-regime propaganda leaflets on the capital Pyongyang. South Korea's military initially denied deploying the drones but has not commented on the matter since.

The North Korean leader's influential sister, Kim Yo Jong, warned on Sunday of a "horrible disaster" if more drones are detected.

In response, Kim held a security meeting on Monday in order to be briefed on "the case of enemy's serious provocation that violated the sovereignty" of North Korea.

The briefing was intended to "set forth the direction of immediate military action," North Korea's state-controlled KCNA news agency reported.