washington u.s. defense secretary jim mattis hint monday existence military options north korea might spare seoul brutal counterattack decline say kind options talk whether involve use lethal force u.s. ambassador unite nations nikki haley say sunday u.n. security council run options contain north korea nuclear program unite state might turn matter pentagon conflict korean peninsula could easily result degree bloodshed unseen since 1950-53 korean war claim live 50,000 americans millions koreans end arm truce peace treaty seoul within artillery range north korea beyond nuclear conventional weapons also believe sizable chemical biological arsenal ask whether military options unite state could take north korea would put seoul grave risk mattis say yes go detail press whether might include so-called kinetic options use lethal force mattis say want go military options available trump range non-lethal action like naval blockade aim enforce sanction wag cyber attack position new u.s. weaponry south korea unite state 28,500 troop south korea raise possibility reintroduce nuclear weapons peninsula mattis acknowledge discuss south korean counterpart decline say whether option consideration open dialogue ally issue want bring say u.s. president donald trump hint use lethal force north korea would overwhelm use phrase like fire fury evoke image nuclear war u.s. military say monday stag bomb drill south korea fly pair b-1b bombers f-35 fighter jet korean peninsula show force north korea still despite heat rhetoric posture unite state north korea position u.s. military assets suggest military conflict imminent trump vow north korea never allow threaten unite state nuclear-tipped missile also ask china rein neighbor china turn favor international response problem mattis tell reporters believe diplomacy sanction far succeed put pressure pyongyang yes work say even tensions rise unite state ally stick hands-off policy north korea test-fires missiles mattis confirm policy monday say would shoot north korean missile unless pose direct threat unite state ally say pyongyang calculus appear design race forward missile program without go kind line mind would make vulnerable mattis hint military options north korea offer detail