An underground tunnel at North Korea's nuclear test site reportedly collapsed. Around 200 people may have been killed.
Japanese media report an initial collapse trapped around 100 people working on tunnel construction. A second collapse reportedly buried more than 100 other people trying to rescue the first group.
It's unclear when all this happened. Officials haven't verified the Japanese report.
North Korea conducted its sixth nuclear test in early September. Shortly after, satellite images showed what experts said were landslides throughout the area on Mount Mantap.
At the time, some Chinese experts warned the mountain might not hold up if the Hermit Kingdom keeps testing.
More recently, analysis group 38 North speculated if the peak could be suffering from "tired mountain syndrome." That happens when nuclear testing fractures the surrounding rock, increasing the risk of radiation seeping into the environment.
Still, experts said they don't think North Korea will abandon the mountain test site.
