korea targeting luxury and imports and exports which help the military. what would hurt north korea more is that the u.s. apply so-called secondary sanctions against kim's chief ally, china. >> it's really well known there's a set of chinese entities that help north korea evade those armed sanctions by the united nations. we've had a lim t number of cases where weave gone after chinese firms for those reasons. we could greatly ex papd their numbers. >> reporter: the president's -- fallen short. tweeting quote, while i greatly appreciate the effort of president xi in china to help with north korean it has not worked out. at least i know china tried. the u.s. say it's looking at a ban to travels to north koreans. -- in any more danger.