A shirtless soldier smashes two glass bottles together, adding to a pile of shards on the ground as North Korean leader Kim Jong Un looks on, grinning.
The man lies down on the debris and a comrade puts a thick concrete block on his chest, before smashing it with a sledgehammer.
The scene was part of a pain-defying display put on by the North Korean army for the opening of a defence exhibition this week that showcased the nuclear-armed country’s weapons.
The soldiers – some in uniform, others topless – punched their way through layers of concrete bricks, or broke them with their heads.
Others were hammered on their arm or hand, and one lay on a bed of nails to have a block broken on his chest.
Leader Kim looked on clapping and smiling, surrounded by officers and with his sister and close adviser Kim Yo Jong at his side, footage on state broadcaster KCTV showed Tuesday.
Korea has a long tradition of martial arts, including its indigenous sport of taekwondo – developed by a South Korean general who later fell out with the South’s military-backed leader Park Chung-hee and became a frequent visitor to Pyongyang, where he died in 2002.
It is now often used by the North to symbolise its military prowess.
“These soldiers, embraced and raised by our party, have demonstrated to the whole world the strength, bravery and morale of the Korean People’s Army,” newsreader Ri Chun Hee – North Korea’s most famous presenter – said over the images.
And Ri did not forget to declare the source of the participants’ strength. It was “bestowed upon them by our dear leader Kim Jong Un”, she said.
The arms exhibition is part of the commemorations for the anniversary of the foundation of the governing Workers’ Party.
On Tuesday at the Defence Development Exhibition, Kim said his country’s weapons development was necessary in the face of “hostile” policies from the US and a military buildup in South Korea that is destabilising the peninsula, state media reported.
Pyongyang was only increasing its military in self-defence and not to start a war, Kim said in a speech, according to a report by state news agency KCNA.
Kim has overseen rapid progress in Pyongyang’s banned nuclear weapons and ballistic missile programmes, which have earned it multiple international sanctions.