beijing north korean nuclear issue need peaceful resolution chinese president xi jinping tell u.s. president donald trump telephone call saturday call relevant side exercise restraint state television say trump issue new threat north korea friday say u.s. military lock load pyongyang accuse drive korean peninsula brink nuclear war world power express alarm xi tell trump joint interest china unite state achieve denuclearisation korean peninsula protect peace stability state television say brief report relevant side must present exercise restraint avoid word action exacerbate tensions korean peninsula report paraphrase xi say resolve nuclear issue ultimately need do politically via talk china will maintain communication unite state basis mutual respect push appropriate resolution xi add chinese state television cite trump tell xi fully understand role china play north korean nuclear issue china 's xi say peaceful resolution need north korea nuclear issue