World unity crumbles in face of North Korea threat

International solidarity in the face of North Korea's nuclear threat crumbled Tuesday as Russia rebuffed US calls for new UN sanctions and Washington promised its allies advanced weaponry.Last month, Pyongyang's latest missile test drew unanimous condemnation from the UN Security Council -- but Sunday's apparent hydrogen bomb detonation revealed an underlying diplomatic rift.Russia's President Vladimir Putin declared Washington's demand for a vote on new UN sanctions to be "useless," while US Pr