In a video broadcast by Korean Central Television (KRT), country's soldiers were seen smashing bricks with their heads, lying on glass and performing other extreme forms of combat display.

Along with other leaders of the hermit nation, North Korean dictator Kim Jong-un applauded the "Self-Defense 2021" exhibition with a wide smile on his face.

The footage, filmed last month, was broadcast on state television, as tensions in the region grew.

In recent weeks, the North has ramped up its rhetoric and made specific threats to target US territory.

North Korea has also apparently deployed a second missile on its east coast.