South Korea, the United States and Japan warned that North Korea's planned rocket launch would violate a UN resolution and said they would take the issue to the Security Council if the North goes ahead with it, a news report said Saturday. North Korea says it will send a communications satellite into orbit between April 4 and 8 as part of a peaceful bid to develop its space program. But some governments suspect the North will use the launch to test technology for a long-range missile capable of striking Alaska. They have denounced the launch as a provocative move banned under a 2006 UN Security Council resolution prohibiting ballistic activity by North Korea, and have warned it would invite international sanctions. "We will immediately discuss the matter at the U.N. Security Council," Japanese nuclear envoy Akitaka Saiki told reporters after talks with his US and South Korean counterparts in Washington, according to Japan's Kyodo news agency.