North Korea, believed to have just activated a key nuclear reactor, now appears set to raise tensions further by preparing to start reprocessing plutonium and test a ballistic missile, officials and reports said on Friday. As South Korea’s new government scrambled to cope with the apparent firing up of the Yongbyon reactor, reports from Tokyo and Washington indicated that the North might be moving to cross what experts call critical ‘‘red lines’’ in the nuclear crisis. US officials and Congressional sources said on Thursday that N Korea was continuing to ready a spent fuel reprocessing plant and could have the facility operating as a source of weapons-grade plutonium in a month. N.Korea media delivers rhetorical blow to US SEOUL: North Korea’s two main newspapers launched a two-pronged rhetorical attack on the US on Friday, saying Washington was full of political imbeciles with a wild ambition to invade the North. “They are painting the military exercises as an “annual event” and “defensive drills”,” the newspaper Minju Joson said. “But this is a penny-worth trick to fool the public opinion at home and abroad.” The party daily Rodong Sinmun said N Korea’s decision to pull out of the Non-Proliferation Treaty, which seeks to halt the spread of nuclear weapons, was a self-defensive measure. (Reuters) These developments are likely to increase calls from Seoul, Beijing and Moscow for the US to talk directly to North Korea — a course Washington has resisted in favour of multilateral diplomatic pressure on Pyongyang. In another sign of brinkmanship, a major Japanese daily reported on Friday that US satellite photos and other intelligence indicated that North Korea had tested a rocket booster in January for a Taepodong ballistic missile capable of hitting Tokyo. Japan’s Defence Minister, Shigeru Ishiba, told reporters he had no information about the report, in the mass-circulation Yomiuri Shimbun, but said Japan did not believe that North Korea was about to launch a ballistic missile. That missile — and longer-range rockets the North is thought to have built but not yet tested — compound worries about the nuclear ambitions of a militant state that also has chemical and biological weapons and the world’s fifth largest standing army. Many US Opposition Democrats and experts believe the Bush administration is foolishly playing down the risk of Pyongyang’s activities and unnecessarily provoking the isolated Communist regime by refusing to engage in direct talks. ‘‘This can’t be resolved without the US and talking to North,’’ said Daniel Pinkston of the Center for Non-proliferation Studies at Montereys Institute in California. ‘‘I can’t see how US interests are served by stalling.’’ (Reuters)