UNITED NATIONS - The UN Security Council will take “very firm and strong” action against any nuclear test by North Korea, the council president said. Kim Sook, South Korea’s UN envoy, said the test appeared “imminent” and any blast would be “a dangerous attempt to undermine the authority and credibility of the Council.” The 15-member council is “unified and they are very firm and resolute. I would expect very firm and strong measures to be taken,” Kim told reporters at the UN headquarters as his country assumed the council’s presidency for Feb. “We cannot sit idly by and do nothing vis-a-vis some devastating provocative action done by North Korea,” he added.