President Lee Myung-bak called Saturday for defense reform to build a stronger military amid lingering tensions with North Korea over its two deadly attacks on the South last year. The North\'s attacks made it clear that \"defense reform is an urgent task that cannot be delayed any longer,\" Lee said in a live televised speech marking the 63rd Armed Forces Day at the military headquarters near Daejeon, south of Seoul. South Korea has accused North Korea of sinking a warship in March last year, killing 46 sailors, but Pyongyang denies any involvement. North Korea also shelled a South Korean border island in November, killing two soldiers and two civilians. The reform plans center on making the military\'s command structure more efficient, giving the chairman of the Joint Chiefs of Staff more power to control the Army, Navy and Air Force to help the armed forces better cope with North Korean provocations. The Cabinet approved a set of defense reform bills in May and sent them to parliament for approval, though no major progress has been made since then. Lee also said the armed forces need fundamental change as South Korea is preparing to take over wartime operational control from the United States in 2015. Under a 2007 deal with the U.S., South Korea had been scheduled to take over control of its armed forces in April 2012 in the event of a war, but the two sides agreed to delay the transfer by three years after the North\'s sinking of the South Korean warship. The U.S. has held wartime command of South Korean troops since the beginning of the 1950-53 Korean War, which ended in an armistice, not a peace treaty. Seoul regained peacetime control of its military in 1994. About 28,500 U.S. troops are stationed here as a deterrent against the North.