200 dead in tunnel accident at North Korean nuclear test

More than 200 people are feared to have died when a tunnel caved in at North Korea's nuclear test site after its latest detonation, a Japanese news report said Tuesday.

A tunnel collapsed at Punggye-ri in early September, days after North Korea conducted its sixth and largest underground nuclear test on September 3, TV Asahi said, quoting unnamed North Korean sources.

Some 100 workers were involved in an initial collapse. Another cave-in occurred during rescue operation ..
Experts have warned that the underground tests could cause the mountain to collapse and leak radiation into the atmosphere near China's border.

The latest test -- the sixth at the site since 2006 -- triggered landslides in the detonation area and beyond, according to satellite pictures taken the day after.

The images published by the 38 North website showed changes in the surface at Punggye-ri where the ground had been lifted into the air by the tremors. Small landslides followed the course of stream beds.

The blast caused a 6.3-magnitude earthquake, according to the US Geological Survey, followed a few minutes later by another with a magnitude of 4.1.

Japan assessed the yield from the test of what the North said was a hydrogen bomb at 120 kilotons, eight times the size o