Amphibious assault vehicles of the South Korean Marine Corps throw smoke bombs as they move to land on shore during a US-South Korea joint landing operation drill in Pohang on March 31. The drill is part of the two countries' annual military training called Foal Eagle, which began on February 24 and runs until April 18.  North Korea declared a no-sail warning on Monday for areas off its west coast near a disputed border with South Korea and has notified the South that it will conduct firing drills, a South Korean government official said. The warning comes amid heightened tensions surrounding the North after the U.N. Security Council condemned Pyongyang for its mid-range missile launches last week, just as the leaders of South Korea, Japan and the United States met to discuss the North's arms programme. Reuters/Kim Hong-Ji