Kim Jong Un: North Korea to take 'substantial measures' against U.S. PYONGYANG, North Korea, Jan. 27 (UPI) -- North Korean leader Kim Jong Un promised to take unspecified "substantial measures" in retaliation against U.S. and U.N. sanctions against missile tests. Kim met with top security and foreign affairs officials Saturday when he instructed military and party officials how to retaliate against the United States, The New York Times reported Sunday. "At the consultative meeting, Kim Jong Un expressed the firm resolution to take substantial and high-profile important state measures in view of the prevailing situation," state-run North's Korean Central News Agency reported. He advanced specific tasks to the officials concerned. While specific measures were not revealed, North Korea's National Defense Commission said Tuesday in a statement its future rocket and nuclear tests may directly target the United States. "In the new phase of our century-long struggle against the United States, we do not hide the fact that various satellites, long-range missiles that we will continue to launch and high-level nuclear test we will conduct will target our sworn enemy, the United States," KCNA quotes the commission as saying South Korean officials warned the North is prepared to conduct a nuclear test at any time from its Punggye-ri underground test site, South Korea's Yonhap news agency reported. North Korea is angry at U.N sanctions against the country after the North launched its second rocket in December. The North said the launch was part of a peaceful space program, but the United States and other countries said it testing its long-rang missile technology.