riyadh u.s. secretary state rex tillerson arrive riyadh saturday attend landmark meet officials saudi arabia iraq aim improve relations two countries counter iran grow regional influence chief u.s. diplomat fly king salman air base little week u.s. president donald trump unveil strategy contain iran compel tehran agree close charge flaw multinational 2015 deal design prevent iran develop nuclear weapons tillerson official meet saturday work dinner saudi foreign minister adel al-jubeir stop saudi arabia first leg six-day trip also take qatar pakistan india switzerland talk sunni muslim-ruled saudi arabia qatar expect dominate topic shi ite-dominated iran grow regional influence iran-backed militias help turn tide syria civil war government favor play lead roles iraq battle recapture islamic state self-declared caliphate week aid iraqi security force seize oil-rich area northern city kirkuk part effort crush bid independence make kurdish minority washington riyadh also allege iran support houthi rebel yemen pro-government force support saudi-led military coalition back unite state yemen grind civil war expect high tillerson agenda sunday tillerson due attend inaugural session saudi-iraqi coordination council body whose creation promote trump administration improve relations saudi arabia iran main regional rival iraq whose majority shi ite-dominated government close tie tehran visit tillerson also expect explore possibility renew push end diplomatic economic boycott qatar saudi arabia u.s. arab ally although concede optimistic interview thursday bloomberg tillerson blame saudi arabia unite arab emirates bahrain egypt lack progress toward end four-month-old crisis saudi arabia ally accuse qatar support hardline islamist group cozying iran region expense doha deny allegations leadership quartet want engage qatar qatar clear ready engage say tillerson forge close tie gulf arab countries former position ceo exxon mobil senior uae official say saturday qatar end crisis ahead summit six-nation gulf cooperation council december ball court aware require minister state foreign affairs anwar gargash write twitter account tillerson land riyadh start gulf south asia tour