from usatoday.com: A barrage of artillery fire between North and South Korea across disputed maritime borders on Monday marked an annual show of force by North Korea intent on sending a message to the U.S. as it conducts military exercises nearby. North Korea's missile launches into the Yellow (West) Sea followed by a threat of live-fire drills along the border "was really aimed at our policymakers, Republic of Korea policymakers and Japan," said Bruce Bechtol, a Korea specialist and professor of political science at Angelo State University in Texas. "North Korea is saying, 'You can do all the exercises you want and we have the ability to hit you at a moment's notice,'" Bechtol said. The U.S. and South Korea routinely conduct joint military exercises in the border areas, usually each year in February and March. The most recent exercise began March 27.