- Collapse took place after Pyongyang's sixth atomic test in September
- 100 workers at Punggye-ri nuclear site affected by initial collapse
- Number of deaths went up to 200 likely after second collapse
Reuters has not been able to verify the report.
About 100 workers at the Punggye-ri nuclear site were affected by the initial collapse, which took place around September 10, the broadcaster said.
A second collapse during a rescue operation meant it was possible the death toll could have exceeded 200, it added.
Experts have said a series of tremors and landslides near the nuclear test base probably mean the country's sixth and largest blast on Sept. 3 has destabilised the region, and the Punggye-ri nuclear site may not be used for much longer to test nuclear weapons.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)