This undated photo released by the official Korean Central News Agency on May 30, 2017 shows a test-fire of a ballistic missile at an undisclosed location (STR/AFP/Getty Images)
A long-range ground-based interceptor successfully intercepted an ICBM target launched from the U.S. Army’s Reagan Test Site. This was the first live-fire test event against an ICBM-class target (Missile Defense Agency, U.S. Department of Defense)
Korean People's Army (KPA) tanks are displayed during a military parade marking the 105th anniversary of the birth of late North Korean leader Kim Il-Sung in Pyongyang on April 15, 2017. (ED JONES/AFP/Getty Images)
U.S. Defense Secretary James Mattis arrives via helicopter at Resolute Support headquarters on April 24, 2017 in in Kabul, Afghanistan. (Jonathan Ernst - Pool/Getty Images)