U.S. Army self-propelled howitzers are on positions during the annual exercise in Pocheon, near the border with North Korea, Thursday, March 10, 2016. North Korea responded to South Korean unilateral sanctions Thursday by firing short-range ballistic missiles into the sea in a show of defiance and vowing to “liquidate” all remaining South Korean assets at former cooperative projects in the North.(AP Photo/Ahn Young-joon)