Although open warfare and strikes across the Gulf have reduced, the impasse continues to weigh on the world economy.
US Secretary of State Marco Rubio voiced hope of progress on ending the war with Iran, as he looked to Pakistani mediators to help advance efforts to strike an agreement.
Previous comments by President Donald Trump had suggested weeks of stop-start negotiations to strike a permanent end to the war were teetering on the "borderline" between a deal and renewed attacks.
"I believe the Pakistanis will be travelling to Tehran today. So hopefully that'll advance this further," Rubio told reporters on Thursday.
A ceasefire on April 8 halted the war launched weeks earlier by the United States and Israel, but negotiation efforts, including historic face-to-face talks hosted in Islamabad, have so far failed to yield a lasting agreement.
