U.S. President Donald Trump (R) speaks at a joint press conference with visiting Canadian Prime Minister Justin Trudeau at the White House in Washington D.C., the United States, on Feb. 13, 2017. U.S. President Donald Trump on Monday vowed to deal with Democratic People's Republic of Korea (DPRK) "very strongly", calling the Asian country a "big, big problem." (Xinhua/Yin Bogu)