North Korea has reportedly established an infantry unit whose members are being trained to carry nuclear devices in backpacks and, in the event of war, to infiltrate the South before detonating their weapons,.

Quoting sources within North Korea, Radio Free Asia said the military was calling on each of the nation's soldiers to become a "nuclear arsenal" in the event of war breaking out in the region.

It is not clear whether the units are suicide squads, similar to the kamikaze units sent to attack Allied warships in the closing days of World War II.

The North Korean military is ramping up the propaganda to its own troops in response to joint military exercises between US and South Korean troops. More than 50,000 South Korea and 25,000 US personnel are taking part in the ongoing Ulchi Freedom Guardian exercises.