NEW YORK, NY - APRIL 28: US Secretary of State Rex Tillerson speaks to members of the security council during a meeting on nonproliferation of North Korea on April 28, 2017 in New York City. The growing threat of a nuclear North Korea is going to be the focus for Secretary of State Rex Tillerson while he chairs a special meeting of the United Nations Security Council. (Photo by Eduardo Munoz Alvarez/Getty Images)

NEW YORK, NY – APRIL 28: US Secretary of State Rex Tillerson speaks to members of the security council during a meeting on nonproliferation of North Korea on April 28, 2017 in New York City. The growing threat of a nuclear North Korea is going to be the focus for Secretary of State Rex Tillerson while he chairs a special meeting of the United Nations Security Council. (Photo by Eduardo Munoz Alvarez/Getty Images)