North Korea says it is cutting off all relations with South Korea after being blamed for sinking a South Korean war ship. The United States said, the decision was not in the best interest of the North Korean people. <br/> North Korea's announcement that it is breaking off all ties with the South comes after an independent report showed that the South Korean warship sunk last March was destroyed by a torpedo. <br/> South Korea has already broken off most economic ties between the two countries and is pursuing the matter at the United Nations. <br/>The American Secretary of State, Hillary Clinton has said, the United States and China will work together to find appropriate and effective response to the Korean crisis. <br/>