About the Author

Leo Byrne
Leo Byrne was the Data and Analytic Director at NK News. Follow him on twitter @LeoPByrne
U.S. Secretary of Defense James Mattis on Sunday said Washington's military response would be "massive" if North Korea threatened the United States, Guam or its allies.
The comments follow a successful North Korean nuclear test which took place in the early hours of Sunday morning (EST). The DPRK claimed it detonated a hydrogen bomb small enough to be mounted on a missile.