North Korea has designated remote Chagang Province as a Special Songun [military-first] Revolutionary Zone, fuelling suspicions that the region is being turned into a mountain redoubt for the regime’s atomic weapons and missile programmes despite Pyongyang’s promises to scrap its nuclear arsenal.

Officials of the Ministry of State Security were informed of the new designation in April, the Seoul-based Daily NK news outlet reported, quoting a high-ranking source in Pyongyang.

The region will become “a strategic foothold for the military in the face of modern warfare”, the source said, adding that the ministry had decreed “the project must go forward without any issues because Kim Jong-un was doing it out of respect for his father’s and grandfather’s legacies”.

Covering more than 6,400 square miles on North Korea’s border with China, fully 98 percent of Chagang is mountainous, meaning it is relatively sparsely populated and has plenty of opportunities for underground excavations to conceal stockpiles of weapons and facilities to conduct further research.

As far back as 2013, South Korea’s National Intelligence Service warned in a report that Kim Jong-un, the North Korean dictator, had ordered that the domestic munitions industry be moved underground to protect it from observation and attack.