The North Korean flag flies above the North Korean Embassy in Beijing, Thursday, April 20, 2017. The U.S. is piling the pressure on Beijing to use its clout with North Korea to rein in its nuclear and missile programs. China is the North's most important trading partner and ally, but Pyongyang has ignored Beijing's calls for a suspension of those programs and its requests for high-level bilateral talks. (AP Photo/Mark Schiefelbein)