washington/moscow u.s. president donald trump dismiss chinese diplomatic effort rein north korea weapons program failure thursday secretary state rex tillerson say beijing lot could limit oil supply pyongyang tweet trump deliver another insult barb north korean leader kim jong un call little rocket man sick puppy north korea test-fired advance missile date wednesday russian foreign minister sergei lavrov say washington approach dangerously provocative trump tweet inflame tensions reignite week north korea say successfully test new intercontinental ballistic missile breakthrough put u.s. mainland within range nuclear weapons whose warheads could withstand re-entry earth atmosphere chinese envoy return north korea seem impact little rocket man trump say twitter day speak chinese president chinese president xi jinping reiterate call beijing use leverage north korea tillerson thursday welcome chinese efforts north korea say beijing could limit oil export country chinese lot think could oil really ask please restrain oil cut completely tillerson say state department china north korea neighbor sole major trade partner trump bellicose time rhetoric toward north korea tillerson persistently hold hop return dialogue north korea show will give nuclear weapons program however tillerson may remain job long disagreements trump north korea one factor thursday senior trump administration officials say white house consider plan replace tillerson mike pompeo director central intelligence agency u.s. defense secretary jim mattis say still confidence diplomatic efforts north korea unite state would unrelenting work unite nations spite trump rhetoric warn options include military ones table deal north korea administration stress favor diplomatic solution crisis trump pledge sanction response late test emergency u.n. security council meet late wednesday unite state warn north korea leadership would utterly destroy war break administration focus one big thing come north korea denuclearization korean peninsula white house spokeswoman sarah sanders tell regular white house brief anything beyond priority point say respond question whether regime change administration agenda trump recent tweet speech u.n. ambassador nikki haley lavrov point joint u.s.-south korean military exercise plan december accuse unite state try provoke kim fly handle missile program hand washington pretext destroy country also flatly reject u.s. call russia cut tie pyongyang nuclear ballistic missile program call u.s. policy toward north korea deeply flaw call trump thursday south korean president moon jae-in say missile launch week north korea advance far unclear whether pyongyang technology miniaturize nuclear warhead still need prove things re-entry technology white house statement say trump moon reiterate strong commitment enhance deterrence defense capabilities u.s.-south korea alliance add leaders reaffirm strong commitment compel north korea return path denuclearization cost north korea test dozens ballistic missiles kim leadership conduct sixth large nuclear bomb test september say weapons program necessary defense u.s. plan invade unite state 28,500 troop south korea legacy 1950-53 korean war deny intention previous u.s. administrations fail stop north korea develop nuclear weapons sophisticate missile program trump previously say unite state would totally destroy north korea necessary protect ally nuclear threat also struggle contain pyongyang since take office january trump china 's north korea diplomacy appear 'no impact little rocket man