June 18 (UPI) -- The powerful sister of North Korean leader Kim Jong-un on Thursday denounced international calls for denuclearization, describing the country's nuclear weapons as its "core interests" and denuclearization as a "line of no retreat that can never be crossed," Pyongyang's state media reported. In a statement carried by the Korean Central News Agency (KCNA), Kim Yo-jong criticized the United States and its allies for making what she called "anachronistic" demands for North Korea's