US President Donald Trump (C) displays an executive order after addressing the International Association of Chiefs of Police Conference at the McCormick Place Convention Center in Chicago, the United States, on Oct. 28, 2019. (Photo by Joel Lerner/Xinhua)

US President Donald Trump speaks at the International Association of Chiefs of Police Conference at the McCormick Place Convention Center in Chicago, the United States, on Oct. 28, 2019. (Photo by Joel Lerner/Xinhua)