hanoi u.s. president donald trump say sunday prepare mediate claimants south china sea five countries contest china sweep claim busy waterway trump speak vietnam become vocal opponent china claim construction militarization artificial islands sea 3-trillion goods pass sea year help mediate arbitrate please let know trump say comment meet hanoi vietnam president tran dai quang trump acknowledge china position south china sea problem good mediator arbitrator say president quang say vietnam believe handle dispute south china sea peaceful negotiations basis international laws vietnam say nullify china claim vietnam reclaim land around reef islets nowhere near scale china brunei malaysia philippines taiwan also claim sea since philippine president rodrigo duterte grow close china vietnam emerge china main challenger region july china pressure vietnam stop oil drill dispute area take relations low relations since improve chinese president xi jinping visit hanoi late sunday south china sea discuss beijing early leg trump 12-day asian tour u.s. secretary state rex tillerson say unite state china frank exchange view unite state anger china freedom navigation patrol close chinese-controlled islands vietnam trump leave philippines last stop tour meet leaders association southeast asian nations asean august foreign minister southeast asian countries china adopt negotiate framework code conduct south china sea although critics see tactic buy china time consolidate power framework seek advance 2002 declaration conduct doc party south china sea mostly ignore claimant state particularly china build seven man-made islands dispute water three equip runways surface-to-air missiles radars party say framework outline code establish critics raise doubt effective pact framework endorse china asean members summit manila monday diplomat one regional bloc countries say next step asean china start formal consultations negotiations actual code conduct early talk start february 2018 diplomat say relations vietnam unite state blossom decades since war end 1975. recent survey put favorability unite state 84 percent among vietnamese vietnam trade surplus remain irritant trump administration 32 billion last year sixth large unite state though less tenth size china s. want get straighten quickly trump say meet prime minister nguyen xuan phuc vietnamese u.s. company sign memorandums understand gas development automobile well aircraft engine purchase support trump visit value deal unclear trump offer mediate south china sea