North Korea's plan to attract foreign investment by setting up economic development zones is doomed to fail unless Pyongyang addresses its nuclear weapons programs, Yonhap News Agency reported Thursday, citing a senior South Korean official. "No one can invest in North Korea properly while tightened UN sanctions remain in place against the country for its nuclear tests," South Korea's senior presidential foreign affairs secretary Ju Chul-ki was quoted as saying in a forum in Seoul. North Korea conducted nuclear tests in 2006, 2009 and February 2013, drawing international condemnation and tougher UN. sanctions. Still, North Korea has said it will simultaneously pursue both nuclear and economic development, calling its nuclear programs a deterrent against what it claims is the US' hostile policy against it. South Korea and the US warned that the North's policy is a dead end for the country. Ju also called on North Korea to follow in the footstep of either Ukraine or Kazakhstan in giving up nuclear weapons in return for economic aid and security guarantees. North Korea has rejected previous calls to emulate Libya, which received a set of political incentives after abandoning its nuclear program.