South Korea has said it will hold a naval drill in October against proliferation of weapons of mass destruction. <br/><br/>In a report to the Parliament, the defense ministry today said the drill is planned as part of responses to the sinking of a South Korean warship in late March, which Seoul blames on the North for torpedo attacking. <br/><br/>Countries involved in the U.S.-led Proliferation Security Initiative (PSI) including Japan, Australia and Singapore, will participate in the exercise slated to be held in waters near the southern port city of Busan. Seoul will also join a separate PSI drill to be held in Australia in September this year.