tokyo u.n. secretary-general antonio guterres warn danger sleepwalk war say thursday security council resolutions north korea nuclear missile program must fully implement pyongyang countries guterres make comment reporters meet japanese prime minister shinzo abe tokyo days u.s. secretary state rex tillerson offer begin direct talk north korea without pre-conditions white house say wednesday negotiations could hold north korea improve behavior white house decline say whether president donald trump take tough rhetorical line toward pyongyang give approval tillerson overture clear security council resolutions must fully implement first north korea countries whose role crucial ... achieve result aim denuclearisation korean peninsula guterres say guterres add security council unity also vital allow possibility diplomatic engagement would allow denuclearisation take place bad possible thing could happen us sleepwalk war might dramatic circumstances say japan say time keep maximum pressure pyongyang start talk north missile nuclear program china russia however welcome tillerson overture abe speak reporters guterres reiterate dialogue need meaningful aim denuclearisation fully agree denuclearisation korean peninsula indispensable peace stability region abe say tillerson overture come nearly two weeks north korea say successfully test breakthrough intercontinental ballistic missile icbm put entire unite state mainland within range september north korea fire ballistic missile northern japanese island hokkaido second fly japan less month north korea appear little interest negotiations unite state develop ability hit u.s. mainland nuclear-tipped missile something experts say still prove unite nations political affairs chief jeffrey feltman visit pyongyang last week say tuesday senior north korean officials offer type commitment talk believe leave door ajar u.n. 's guterres warn 'sleepwalking war north korea