The U.S.-based Web site 38 North reports that tunnel work apparently continues to take place at North Korea’s Punggyeri nuclear test site.
 
Citing recent commercial satellite imagery, 38 North said Monday that there has been a consistently high level of activity at the site's Western portal since North Korea’s sixth nuclear test.
 
The report said such activities “includes a routine presence of vehicles and personnel around the portal, movement of mining carts from the portal to the adjacent spoil pile and signs of fresh spoil being dumped onto the pile.”
 
The report assessed that such activities “suggest that tunnel excavation is underway at the West Portal, as the North Koreans expand the site’s potential for future nuclear testing.”