South Korea Koreas Tension

A rocket is fired from an M777 155mm Howitzer of the U.S. Marines from the 1st Marine Division, 11th Marines, Camp Pendleton, California, during the annual joint military exercises, dubbed Key Resolve and Foal Eagle, between the United States and South Korea, at the U.S. Army's Rodriguez Range in Pocheon, north of Seoul, South Korea, Monday, March 15, 2010. (AP Photo/ Lee Jin man)

A rocket is fired from an M777 155mm Howitzer of the U.S. Marines from 1st Marine Division, 11th Marines, Camp Pendleton, California, during the annual joint military exercises, dubbed Key Resolve and Foal Eagle, between the United States and South Korea, at the U.S. Army's Rodriguez Range in Pocheon, north of Seoul, South Korea, Monday, March 15, 2010. (AP Photo/ Lee Jin man)

U.S. Marines from the 1st Marine Division, 11th Marines, Camp Pendleton, California, hold their weapons during the annual joint military exercises, dubbed Key Resolve and Foal Eagle, between the United States and South Korea, at the U.S. Army's Rodriguez Range in Pocheon, north of Seoul, South Korea, Monday, March 15, 2010. (AP Photo/ Lee Jin man)

U.S. Marines from 5th Marine Regiment, based in Camp Pendleton, California, march after a live fire drill during the annual joint military exercises, dubbed Key Resolve and Foal Eagle, between the United States and South Korea, at U.S. Army's Rodriguez Range in Pocheon, north of Seoul, South Korea, Friday, March 12, 2010. U.S. troops who would be tasked with eliminating North Korea's weapons of mass destruction in the event of armed conflict are participating in military drills with South Korea, the top U.S. commander in the country said Thursday. (AP Photo/ Lee Jin man)

U.S. Marines from 5th Marine Regiment, based in Camp Pendleton, California, check their weapons after a live fire drill during the annual joint military exercises, dubbed Key Resolve and Foal Eagle, between the United States and South Korea, at U.S. Army's Rodriguez Range in Pocheon, north of Seoul, South Korea, Friday, March 12, 2010. U.S. troops who would be tasked with eliminating North Korea's weapons of mass destruction in the event of armed conflict are participating in military drills with South Korea, the top U.S. commander in the country said Thursday. (AP Photo/ Lee Jin man)

U.S. Marine from 3rd Marine Division, based in Okinawa, Japan, take position with South Korean Marines during the annual joint military exercises, dubbed Key Resolve and Foal Eagle, between the United States and South Korea, at U.S. Army's Rodriguez Range in Pocheon, north of Seoul, South Korea, Friday, March 12, 2010. U.S. troops who would be tasked with eliminating North Korea's weapons of mass destruction in the event of armed conflict are participating in military drills with South Korea, the top U.S. commander in the country said Thursday. (AP Photo/ Lee Jin man)

U.S. Marine from 3rd Marine Division, based in Okinawa, Japan, participate with South Korean Marines in the annual joint military exercises, dubbed Key Resolve and Foal Eagle, between the United States and South Korea, at U.S. Army's Rodriguez Range in Pocheon, north of Seoul, South Korea, Friday, March 12, 2010. U.S. troops who would be tasked with eliminating North Korea's weapons of mass destruction in the event of armed conflict are participating in military drills with South Korea, the top U.S. commander in the country said Thursday. (AP Photo/ Lee Jin man)

A U.S. Marine from 3rd Marine Division, based in Okinawa, Japan, takes a position with South Korean Marines during the annual joint military exercises, dubbed Key Resolve and Foal Eagle, between the United States and South Korea, at U.S. Army's Rodriguez Range in Pocheon, north of Seoul, South Korea, Friday, March 12, 2010. U.S. troops who would be tasked with eliminating North Korea's weapons of mass destruction in the event of armed conflict are participating in military drills with South Korea, the top U.S. commander in the country said Thursday. (AP Photo/ Lee Jin man)

A South Korean Marine, right, is about to throw a smoke grenade as U.S. Marine from 3rd Marine Division, based in Okinawa, Japan, look on during the annual joint military exercises, dubbed Key Resolve and Foal Eagle, between the United States and South Korea, at U.S. Army's Rodriguez Range in Pocheon, north of Seoul, South Korea, Friday, March 12, 2010. U.S. troops who would be tasked with eliminating North Korea's weapons of mass destruction in the event of armed conflict are participating in military drills with South Korea, the top U.S. commander in the country said Thursday. (AP Photo/ Lee Jin man)

An anti U.S. protester shouts slogans against the annual joint military exercise, dubbed Key Resolve and Foal Eagle, between the United States and South Korea as South Korean police officers block the gate in front of U.S. Army's Rodriguez Range, in Pocheon, north of Seoul, South Korea, Monday, March 15, 2010. The Korean read Stop, War exercise. (AP Photo/ Lee Jin man)

South Korean Marines aim their weapons during the annual joint military exercises, dubbed Key Resolve and Foal Eagle, between the United States and South Korea, at U.S. Army's Rodriguez Range in Pocheon, north of Seoul, South Korea, Friday, March 12, 2010. U.S. troops who would be tasked with eliminating North Korea's weapons of mass destruction in the event of armed conflict are participating in military drills with South Korea, the top U.S. commander in the country said Thursday. (AP Photo/ Lee Jin man)

South Korean soldiers walk by displays of mock North Korea's Scud B missile, back right, and other South Korean missiles at Korea War Memorial Museum in Seoul, South Korea, Tuesday, Nov. 23, 2010. North Korea shot dozens of rounds of artillery onto a populated South Korean island near their disputed western border Tuesday, military officials said, setting buildings on fire and prompting South Korea to return fire and scramble fighter jets. (AP Photo/Lee Jin man)