U.S. intelligence has proof that North Korean nuclear materials ended up in Libya, the top U.S. envoy on the standoff over Pyongyang’s nuclear program said Thursday, as he expressed concern about the potential for more proliferation by the isolated communist nation. Christopher Hill, outgoing U.S. ambassador to South Korea, also told The Associated Press he would travel to China soon to push for a resumption of international disarmament talks with North Korea — his first trip after moving next week to Washington to become the U.S. assistant secretary of state for East Asian and Pacific affairs. Full Story