Work underway at NKorean nuclear test facility: US officials
Unidentified US officials were quoted as saying Tuesday that American spy satellites have detected a resumption of activity at an underground nuclear test site in North Korea, apparently at one of the facility's tunnels. The officials said it was not clear whether the discovery indicates that Pyongyang is on the verge of detonating another nuclear weapon.
On June 13, US Defense Secretary James Mattis said the North's "continued pursuit of nuclear weapons and the means to deliver them had increased in pace and scope" and "had not abated despite UN censure and sanctions."
The North conducted its fifth and largest nuclear test in September 2016.