North Korea has blown up an inter-Korean liaison office building located just north of South Korea's highly-fortified border in a sensational showcase of rage that raises unrest sharply on the Korean peninsula and puts more pressure on Washington and Seoul in the face of a stalled nuclear diplomacy.

The destruction of the building, which sat on the North Korean territory and had no South Koreans assigned to work in the office, is purely symbolic, but the act by the North is probably the most inflammatory thing the country has committed since it joined nuclear diplomacy in 2018 after a US-North Korean stalemate had many becoming fearful of a war.

The move comes merely hours after Pyongyang renewed threats of using military force at the Korean border. The building was opened in 2018 to help the Koreas - technically in a state of war - to communicate. The area had been left empty since January due to the novel coronavirus restrictions.

In a statement, South Korea warned that it would respond strongly if North Korea continues to worsen the situation. The destruction of the liaison building, Seoul said, dashed the hopes of all concerned who "wanted the development of inter-Korean relations and peace settlement in the Korean Peninsula," BBC News reported, as posted on Yahoo News.

Video of the blast made public by South Korea's presidential Blue House showed an explosion rolling across several infrastructures just across the boundary in Kaesong, with an adjacent tower partially crumbling as thick clouds of smoke billows up in the sky.

According to analysts, North Korea may be seeking to build up a crisis to ramp up pressure on its neighbor while nuclear discussions with the United States are still in a deadlock.

With communications cut, Seoul now has fewer options to ease down the tense situation, which could make a military response more possible. But at least one observer disclosed that the worsening of frictions had been carefully stage-managed.

Kim Yo Jong, North Korean dictator Kim Jong Un's sister and trusted aide, threatened to take down the building in a media release on Saturday, calling it "useless."

In a press release that commemorated the second anniversary of US President Donald Trump's meeting with Kim Jong Un, Pyongyang stated it would continue to fast-track the production of its nuclear arsenal in order to establish a more dependable force to deal with the long-term military threats from the US.

Meanwhile, South Korea's Ministry of Defence separately disclosed that it was closely keeping an eye on North Korean military activities and is ready to strongly counter any future provocation.