U.S. Warns N. Korea of 'Overwhelming' Response to Nuclear AttackDefense Secretary James Mattis has warned North Korea that any use of nuclear weapons against the U.S. or allies would be met with what he called an &Mattis Warns North Korea of 'Overwhelming' Response to Nuclear Use00:39Link copiedFeb. 3, 2017, 8:44 AM UTC / Updated Feb. 3, 2017, 8:44 AM UTC