North Korea's most advanced long-range missile is being assembled at a launch site for a possible test-firing later this month, a newspaper said. Washington urged Pyongyang not to take any "provocative" actions that could undermine peace efforts. The Taepodong-2 missile has recently been moved to the Musudan-ni site on the North's eastern seaboard, but it has not yet been seen near the launch pad, South Korea's mass-circulation Chosun Ilbo reported Friday. "We assume that they are currently assembling the first- and second-stage rockets," the newspaper quoted an unidentified South Korean government official as saying. The National Intelligence Service, Seoul's top spy agency, said it could not confirm the report, citing the sensitivity of intelligence matters.