http://story.news.yahoo.com/news?tmpl=story&u=/ap/20021231/ap_on_re_as/koreas_nuclear_119 N. Korea Accuses U.S. of Plotting War SEOUL, South Korea - North Korea (news - web sites) accused the United States on Tuesday of planning an invasion and vowed to fight "to the last man," hours after it expelled two U.N. monitors, leaving its feared nuclear program shrouded in secrecy. Escalating the crisis, North Korea's ambassador to Moscow was cited by Russian news agencies as saying that because of U.S. pressure Pyongyang could not make good on its commitments under the nuclear nonproliferation treaty, which is designed to halt the spread of nuclear weapons. <b>Ambassador Pak Ui Chun said that Washington had threatened North Korea "with a pre-emptive nuclear strike," the Interfax news agency reported.</b> "These conditions also make it impossible for us to abide by the treaty, whose main provision bans nuclear powers from using nuclear weapons against countries that do not have them." Meanwhile, U.S. officials said they were considering using heavy economic pressure on the communist North to give up its nuclear ambitions. North Korea blamed Washington for raising tensions over its nuclear issue. "The U.S. is stepping up preparations for a war against (North Korea), persistently turning aside the latter's constructive proposal for concluding a nonaggression treaty," said the North's official newspaper, Rodong Sinmun. "If the enemy invades even an inch of the inviolable territory of (North Korea), the people's army and people of will wipe out the aggressors to the last man," the report said. South Korea's President-elect Roh Moo-hyun raised doubts about a possible U.S. strategy to contain North Korea. He worries that pressure could backfire and trigger armed conflicts on the world's last Cold War frontier. More than two million troops are massed on both sides of the Korean border. "I am skeptical whether so-called `tailored containment' reportedly being considered by the United States is an effective means to control or impose a surrender on North Korea," Roh told reporters. The Koreas were divided in 1945. The 1950-53 Korean War ended in an armistice agreement, not in a peace treaty.