UNITED NATIONS -- The UN Security Council has issued an 11th hour warning to North Korea to cooperate with international nuclear inspectors before it considers further measures, including economic sanctions.Inspectors from the International Atomic Energy Agency broke off talks with North Korea Friday after Pyongyang refused proper tests of fuel rods to determine if materials were diverted to a clandestine nuclear weapons program.The council, at an emergency late Monday meeting called by the United States, "strongly" urged North Korea to comply with IAEA demands and expressed fears that Pyongyang was making it impossible to determine the history of its nuclear reactor.The United States suspects North Korea has reprocessed fuel rods into bomb-grade plutonium during the last refueling of the reactor in 1989, when IAEA inspectors not present.All 15 council members, including China, approved a policy statement that also asked the IAEA to keep its two inspectors in North Korea and attempt to negotiate again.The statement contained a veiled threat of further action by saying the council would consider the controversy again in order to achieve "full implementation." But it did not directly refer to sanctions or any other measures.In Tokyo, Japanese Foreign Minister Koji Kakizawa said North Korea had already replaced 4,800 of the 8,000 fuel rods."This means that the next two days or thereabouts will be crucial," he told a news conference.If North Korea does not comply, council members say the next step is an official report from the IAEA saying it cannot guarantee that Pyongyang has complied with the nuclear nonproliferation treaty it signed.After the report, several council members are expected to push for economic sanctions, in hopes China will not block such a move.