The US government has condemned the sinking of a South Korean navy ship as an act of aggression by North Korea.
South Korea says there's overwhelming evidence that a North Korean submarine fired a torpedo that sank the ship, and that has been backed up by a team of international investigators - including experts from the United States, Britain and Sweden - who spent weeks examining the wreck of the Chonan.
Forty-six lives were lost when the ship went down in March while on patrol near the North Korean border.
North Korea denies however that it was responsible and has theatened full-scale war if further sanctions are imposed.
South Korea says parts of the torpedo recovered from the scene off the Korean peninsula's west coast were compatible with a North Korean-made weapon that South Korea secured seven years ago.