Announcement of new economic penalties marks first American response to attack on Saudi Arabia, which US has blamed on Tehran

Appointment of Robert C. O'Brien, special presidential envoy for hostage affairs at the State Department, announced on Twitter

US president facing competing urges of keeping up pressure on Tehran to negotiate while deterring any further Iranian attacks and avoiding another Middle East war

Corey Lewandowski, former campaign manager for US president, says that questions focus on 'petty and personal politics,' mostly keeps mum, following White House orders

Secretary of State to meet with leaders in Riyadh as some in US push for military action against Iran following assault on massive energy facility

US president has the world on tenterhooks over his response to a weekend attack on Saudi oil facilities that his top diplomat has blamed on the Iranians

As hawkish Republicans urge the president to weigh an attack over oil facility assault, Democrats invoke need for Congressional authorization

As tensions rise between Tehran and Washington, Trump says his forces are 'locked and loaded'

After saying earlier that US was 'locked and loaded,' president seems intent on consulting allies before taking action

US president, who has featured prominently in Netanyahu's campaign, says 'big' vote in Israel appears to be a toss-up