Japan says North Korea test and capability pose grave threat

TOKYO (Reuters) - North Korea's conducted a nuclear test on Friday and, combined with advances made by the Pyongyang regime in mobile ballistic missile technology, posed a grave threat to Japan, Defence Minister Tomomi Inada said. "We can't deny the possibility that North Korea is miniaturizing a device to build a warhead," Inada said at a press briefing in Tokyo. He also said the magnitude of the tremor suggested it was not a test of a hydrogen device. (Reporting by Nobuhiro Okubo; writing by T