At least 100 were crushed in the tunnel, and another 100 crushed in a second collapse rescue efforts, reports Japanese TV.
Reports state the collapse was in an “unfinished” tunnel being constructed at the mountain site Punggye-ri.
There have been fears a major collapse could also release radioactive material over the Korean Peninsula.
Chief of South Korea’s weather agency Nam Jae-cheol warned another nuclear blast could trigger a collapse of the North’s mountainous test site.
North Korea tested its biggest ever nuclear bomb earlier this year – detonating its first ever H-bomb.
Since then, inexplicable earthquakes have been detected at the test range, suggesting it was unstable.
Meanwhile, Paul Richards, a seismologist at Columbia University’s Lamont-Doherty Earth Observatory, said: “What we are seeing from North Korea looks like some kind of stress in the ground.
“In that part of the world, there were stresses in the ground, but the explosions have shaken them up.”
Tensions continue to rage between the West and North Korea over Kim’s quest for nuclear ICBMs.
Pyongyang has been silent since September 15 – not carrying out any nuclear or missile tests since firing one over Japan.
There are now fears Kim could make good on his threat to fire the dreaded “Juche Bird”.
खबरसाइट डट कम (www.khabarsite.com) तपाईँको आफ्नै खबर साइट हो । हामी कुनै पनि आग्रह र पूर्वाग्रहरहित भएर हरेक पल सत्य तथ्य निष्पक्ष खबर पस्कने जमर्को गर्छौँ । हाम्रो यस स्वतन्त्र अभियानमा तपाईँको साथ अपरिहार्य छ ।
