<p><br /> North Korea says it has sent a letter to the UN Security Council rejecting an argument by South Korea that it was behind the sinking of its neighbour's navy ship and claiming it was the victim of a US-mastermined conspiracy.<br /> </p><p><br /> The letter comes after the filing of a complaint by the South last week demanding international community action to deter further provocation by Pyongyang.<br /> </p><p><br /> A team of international investigators led by South Korea's military said in May that a North Korean submarine torpedoed its corvette Cheonan on March 26, snapping the vessel in half in a blast and killing 46 sailors.<br /> </p><p><br /> North Korea, through its official media, has rejected the charge saying it was a ploy by the South's President Lee Myung-bak aimed at political gains for his conservative government.<br /> </p><p><br /> North Korea drove tensions to new heights in recent weeks by threatening war if Seoul imposed sanctions, denying any role in the sinking of the Cheonan.<br /> </p><p><br /> The mounting antagonism between the two Koreas has unnerved financial investors, worried about armed conflict breaking out in the region.<br /> </p>
