SEOUL - North Korea threatened to attack rival South Korea if Seoul joined a new round of tightened U.N. sanctions, as Washington unveiled more of its own economic restrictions following Pyongyang's rocket launch last month. In a third straight day of fiery rhetoric, the North directed its verbal onslaught at its neighbor on Friday, saying: "'Sanctions' mean a war and a declaration of war against us." The reclusive North has this week declared a boycott of all dialogue aimed at ending its nuclear program and vowed to conduct more rocket and nuclear tests after the UN Security Council censured it for a December long-range missile launch. "If the puppet group of traitors takes a direct part in the U.N. 'sanctions,' the DPRK will take strong physical counter-measures against it," the North's Committee for the Peaceful Reunification of Korea said, referring to the South. The committee is the North's front for dealings with the South. DPRK is short for the North's official name, the Democratic People's Republic of Korea. The UN Security Council unanimously condemned North Korea's December rocket launch on Tuesday and expanded existing U.N. sanctions. On Thursday, the United States slapped economic sanctions on two North Korean bank officials and a Hong Kong trading company that it accused of supporting Pyongyang's proliferation of weapons of mass destruction. The company, Leader (Hong Kong) International Trading Ltd, was separately blacklisted by the United Nations on Wednesday. Seoul has said it will look at whether there are any further sanctions that it can implement alongside the United States, but said the focus for now is to follow Security Council resolutions. The resolution said the council "deplores the violations" by North Korea of its previous resolutions, which banned Pyongyang from conducting further ballistic missile and nuclear tests and from importing materials and technology for those programs. It does not impose new sanctions on Pyongyang. The United States had wanted to punish North Korea for the rocket launch with a Security Council resolution that imposed entirely new sanctions against Pyongyang, but Beijing rejected that option. China agreed to U.N. sanctions against Pyongyang after North Korea's 2006 and 2009 nuclear tests. North Korea's rhetoric this week amounted to some of the angriest outbursts against the outside world coming under the leadership of Kim Jong-un, who took over after the death of his father Kim Jong-il in late 2011. On Thursday, the North said it would carry out further rocket launches and a nuclear test, directing its ire at the United States, a country it called its "sworn enemy".
