South Korean police officers aim their machine guns during an anti-terror drill as part of Ulchi Freedom Guardian exercise, in Goyang, South Korea, Monday, Aug. 21, 2017. U.S. and South Korean troops kicked off their annual drills Monday that come after U.S. President Donald Trump and North Korea exchanged warlike rhetoric in the wake of the North's two intercontinental ballistic missile tests last month. (AP Photo/Ahn Young-joon)