North Korea is digging a new tunnel at its nuclear test site with an eye to conducting more tests of atomic devices in the future, a South Korean news report said on Friday, two days before the leaders of the South, Japan and China meet in Seoul.U.S. Defense Secretary Ashton Carter also makes a separate visit on Sunday to discuss response to the North's missile and nuclear threat with South Korean defense officials.
The site is on North Korea's east coast where three previous nuclear tests were conducted, and there's an active movement of workers and vehicles working on a new tunnel, Yonhap news agency quoted an unnamed government source as saying.