Japan and the United States sent a fresh warning to North Korea today against test-firing a missile, as the allies agreed to step up efforts to stop a launch that would disturb regional peace, The Associated Press quoted the Japanese Foreign Ministry as saying. Stephen W. Bosworth, the new U.S. envoy on the North, and his Japanese counterpart, Akitaka Saiki, agreed «to urge North Korea not to take an action that would harm the region's peace and stability,» the ministry said in a statement. The two envoys said a launch _ even that of a satellite as Pyongyang claims _ would violate U.N. Security Council resolutions, and agreed to cooperate, along with Seoul, to achieve denuclearization of the Korean peninsula, the ministry said.