( LEAD ) Conservative candidate vows more missile shields , joint management of U . S . nuke assets ( ATTN : RECASTS lead paras to clarify Yoo ' s campaign pledge does not include deployment of U . S . nuclear arsenal in South Korea ; UPDATES with additional information in paras 6 - 7 ) SEOUL , April 5 ( Yonhap ) -- Yoo Seong - min , the presidential nominee of the Bareun Party said Wednesday if elected he would upgrade the country ' s deterrence against North Korean threats by introducing more U . S . missile defense systems and pushing for joint operation of U . S . nuclear assets . Laying out his security - related election pledges , the candidate of the splinter conservative party said that " currently , the United States single - handedly makes most decisions regarding its nuclear assets . " " I will demand a higher level of cooperation ( between Seoul and Washington ) than the one between the U . S . and NATO through a summit and talks between defense and foreign ministers that will be held immediately after my inauguration and win the United States ' concession , " he said . Yoo explained that a higher level of cooperation over U . S . nuclear capabilities will include the U . S . sharing or providing information on such capabilities and joint decisions on the possible use of such capabilities here . Yoo Seong - min , a lawmaker and presidential candidate of the conservative Bareun Party , announces his security - related election pledges at party headquarters in Seoul on April 5 , 2017 . ( Yonhap ) He also proposed devising manuals for joint military exercises involving the possible use of the U . S . nuclear arsenal . The U . S . currently does not physically maintain nuclear capabilities on the Korean Peninsula as it withdrew its tactical nuclear weapons from the country in the early 1990 s . However , Washington frequently reaffirms that its Asian ally is under its nuclear umbrella , meaning it will bring such weapons here if and when necessary . Yoo said he will also deploy additional units of the controversial U . S . air defense system , Terminal High Altitude Area Defense system or THAAD , at the country ' s own expense . The U . S . Forces Korea is in the process of deploying one THAAD battery to Seongju , located some 300 kilometers south of Seoul . The presidential contender said one or two more THAAD batteries would enable multi - layered defense and protection against North Korean missiles . He said he expected each additional THAAD unit to cost the country about 1 trillion won ( US $ 890 million ) . Yoo said he will gradually increase the country ' s defense budget to 3 . 5 percent of its gross domestic product from the current 2 . 4 percent if elected . bdk @ yna . co . kr ( END )