beijing/washington chinese president xi jinping u.s. president donald trump speak keep pressure north korea economic sanction impose unite nations white house say statement monday unite state south korea separately russia together china carry military drill show force north korea defy u.n. security council resolutions conduct nuclear test ballistic missile test trump xi speak phone days trump aid publicly discuss potential military action north korea friday deliver address military base outside washington trump say confident ever options address threat effective overwhelm trump attend annual unite nations general assembly new york week xi north korea nuclear threat likely loom large agenda two leaders also discuss trump come china visit xinhua news agency say xi say china unite state share extensive common interest see sound momentum exchange cooperation various areas present xinhua say xi call side work closely ensure fruitful trip inject new impetus development sino-u.s. relations report say chinese leader say happy maintain communications u.s. leader regular basis topics mutual concern say trump likely visit china november part trip take asean summit philippines apec summit vietnam xi trump discuss sanction pressure north korea white house