North Korea and South Korea exchanged artillery shell rounds as a North Korean military exercise crossed into South Korean waters Monday.
North Korea fired more than 100 military rounds into South Korean waters, causing South Korea to retaliate with 300 rounds. Residents of the South Korean islands fled to bomb shelters as the bombing crossed the border in the Yellow Sea.
South Korean military exercises in the area and "threatening" military drills by U.S. forces in southern waters have angered North Koreans. However, South Korea said no shells were fired at land or military installations on either side, suggesting this was further intimidation and saber-rattling from North Korea.
North Korea has grown frustrated from the lack of outside aid, and has South Korea and other nations worried this could cause an increase once again to daily war rhetoric and further nuclear tests.