This satellite image, provided by U.S. research monitoring website 38 North on Jan. 11, 2018, shows the nuclear test site in the Punggyeri region in North Korea on Dec. 28, 2017. The website claimed North Korea has carried out significant tunneling on the west side of its main nuclear test site, saying these activities underscore Pyongyang’s continued efforts to maintain the site’s potential for future nuclear testing. (Yonhap)
