After a series of six missile tests in quick succession, North Korea has been quieter of late, keeping up its fiery rhetoric but not launching rockets.
It is now suspected this is due to a tunnel collapse that killed 200 workers at the Punggye-ri testing facility at some point after the sixth test in September.
Experts had warned a collapse was likely if missile testing continued, but Japanese TV today reported the devastating accident had already happened.
They could not clarify when the accident and subsequent doomed rescue attempts took place.
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But the deaths could spell the end for the secretive dictatorship’s nuclear programme as the test site could now be too dangerous for further launches.
Desperate North Korean leader Kim Jong-un may struggle to find a new test site which will not suffer the same stresses as the facility at Punggye-ri.
One hundred people were killed when when an unfinished tunnel collapsed at Kim Jong-un's main nuclear testing site. It is estimated another 100 subsequently died while attempting to rescue the first group of entombed workers.
Mount Mantap before the nuclear tests at Punggye-ri
Damage to the test site after six aggressive nuclear tests
The collapse does not appear to have released any radioactive fallout, however it may have destabilised the site so much the it cannot take further tests.
The disaster could also have seriously depleted the workforce in the nuclear facility.
The end of its nuclear programme would no doubt be devastating to bullish North Korean officials however it would calm the fears of its neighbouring counties.
South Korea and Japan have both slammed the nuclear programme while the US has threatened to rain fire and fury on the hermit dictatorship if nuclear provocations continued.
An aerial view of the mountainous region before nuclear tests are carried out
The mountain has shifted and begun to collapse after repeated blasts
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North Korean leader Kim Jong Un provides guidance on a nuclear weapons program in this undated photo released by North Korea's Korean Central News Agency
Punggye-ri was the site of North Korea’s sixth-ever nuclear test on September 3. They tested a huge 100-kiloton explosive which was around seven times as powerful as the bomb dropped on Hiroshima during the Second World War.
This test is believed to have badly destabilised the mountainside facility.
Subsequent small earthquakes have since indicated the area was becoming increasingly unstable.
While satellite images have showed huge changes to the mountain landscape where the missiles have been tested.
North Korea has insisted it will continue to develop nuclear weapons as “a matter of life and death” – however the catastrophe at the test site could be an obstacle to the plans.