South Korea must swiftly carry out the reform of its top military command structure in order to avoid a potential security void in 2015, when Seoul takes back wartime operational control of its troops from Washington, a presidential security adviser said Wednesday. The remarks by Lee Hee-won come amid efforts by the Defense Ministry to get bills on the command reform passed this month at the National Assembly, nearly three months after unveiling a package of military reform measures in response to North Korea\'s two deadly attacks last year. The reform bills would allow the chairman of the Joint Chiefs of Staff to wield more power and transform the top-heavy military into an efficient force with the aim of enhancing the interoperability among the Army, Navy and Air Force. Military observers have raised questions that a delay in the command reform could trigger confusion between South Korean and U.S. forces here, given the transition timetable of wartime operational control (OPCON). \"From 2013, South Korea and the U.S. plan to jointly assess the South\'s military capability regarding the transition of OPCON,\" Lee said at a forum organized by the Army. Lee, a career military man, said the South\'s military needs to complete reforming the top command structure by the end of 2012 for the joint assessment. \"Those things would be possible only if the proposed reform measures are fixed this year,\" Lee said. The U.S. has held wartime command of South Korean troops since the beginning of the 1950-53 Korean War, which ended in a truce, 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. When wartime operational control is handed over to South Korea in 2015, the South\'s military will take charge with support from U.S. troops.