South Korea has asked United Nations Security Council action over the sinking of a South Korean warship in March allegedly by North Korea. <br/> <br/>A letter handed to the Security Council in New York by Seoul's UN ambassador Park In-kook asks the 15-nation body to take action to deter "further provocation by North Korea." The letter does not specify how Seoul wants the Council to respond to the sinking of the navy corvette Cheonan on March 26. <br/> <br/>Possible actions include sanctions or a resolution or statement condemning Pyongyang's behavior.<br/> <br/>South Korea has blamed the North for torpedoing the Cheonan, killing 46 sailors. The North denies responsibility and has accused the South of staging the incident to help Mr Lee in local elections this week.