U.S. President Donald Trump and First Lady Melania Trump depart from the White House in Washington D.C., the United States, on Aug. 24, 2018. U.S. President Donald Trump on Friday tweeted that he has asked Secretary of State Mike Pompeo to cancel his upcoming trip to the Democratic People's Republic of Korea (DPRK), citing the lacking of progress on the Peninsula denuclearization. (Xinhua/Ting Shen)