North Korea unveils first tactical, nuclear-armed submarine

North Korea has launched its latest submarine, with the ceremony attended by leader Kim Jong Un.

A modified Russian design, it uses a diesel engine that can in turn charge a series of batteries, allowing the submarine to run virtually silent when needed. Diesel-electric propulsion is a decades-old technology, but North Korea has radically altered the design, stretching the sail to include some missile launch tubes.

Analysis of the photos of this new submarine, named Hero Kim Kun Ok, suggests it can silently transport and launch 10 Pukguksong-3 missiles while still submerged.

This is a huge leap in capabilities for North Korea.