North Korean dictator Kim Jong-un vowed to see his rivals 'plunge into despair' as he ramped up nuclear attack simulations that involved the detonation of an underwater drone capable of unleashing a "radioactive tsunami".
The state news agency, KCNA, said that the weapon was a "nuclear underwater attack drone" that can be deployed "at any coast and port or towed by a surface ship for operation".
Pyongyang has stepped up its weapons demonstrations in recent months in response to military exercises between the United States and its ally South Korea aimed at countering the North's growing nuclear threat.
