Lawmakers are concerned about high civilian causalities from Riyadh-led military campaign in Yemen and Trump administration's use of emergency protocol to approve $8 billion deal

Graham, usually a Trump backer, tells Riyadh: 'There is no amount of oil that will give you a pass on chopping somebody up in a consulate'

John Bolton visit coincides with regional summits in Saudi Arabia, as US and Arab allies seek to further isolate Iran

Democrat senators rebuke administration for turning to rarely used provision, which allows for weapons sales without congressional review

Figures show a decline compared to 2017 due to that year's $2.5 billion missile deal with India and 2018's cancelled contract to sell F-16 jets to Croatia