They have reverted to more subtle threats.

North Korea appears to have revealed details of two as-yet untested missile systems in its press coverage of a factory inspection by the country’s Supreme Leader Kim Jong-un.

Photographs released by KCNA state news agency to go with a report on Mr Kim’s visit to a facility at the Academy of Defence Sciences facility show wall charts describing the missiles, called Hwasong-13 and Pukguksong-3.

Hwasong-13 appears to be a three-stage ICBM (Inter Continental Ballistic Missile), while the chart showing Pukguksong-3, although largely obscured by officials, is an Submarine Launched Ballistic Missile (SLBM).

It’s not the first time that North Korea has “accidentally” left details of important developments in the background of photo-shoots, and this is seen by analysts as a means of showing off its military power or sending messages to its foes.