Meanwhile, Iraqi Oil Minister Jabar al-Luaibi said on Wednesday that OPEC will discuss a possible shortfall in global crude oil supplies following Trump's decision to withdraw from the Iran nuclear deal. Saudi Arabia has resisted making a similar unconditional pledge.
US Secretary of State Mike Pompeo, left, is greeted by Saudi King Salman in Riyadh, Saudi Arabia.
The sanctions could impact Iran's ability to export oil.
Despite US criticism that the accord does not go far enough in monitoring Iran's nuclear activities, the IAEA points to the fact that its inspectors have spent 3,000 man days per year on the ground in Iran. Yet, even in the case that Saudi Arabia keeps to its schedule, the US nuclear industry could still play an important role.
Saudi Arabia's air defences intercepted two ballistic missiles over Riyadh on Wednesday, state media said, the latest in a series of attacks claimed by Iran-allied rebels in neighbouring Yemen.
To secure an agreement with the United States that will pass Congress, the Saudis may agree on a moratorium on enrichment and reprocessing.
Saudi media outlets and commentators also had praise for Trump's controversial move.
"One thing that has changed and which I think is clearly a new development is that it seems to me that the White House administration has really pushed Saudi Arabia to do something about price and to put supply back into the market to make sure prices do not run up. before (when sanctions were last in place) Saudi Arabia was driving its own oil policy".
It was the busiest day in USA front-month contracts since August, and for Brent the busiest in nearly a month. Countries seeking exceptions "are advised to reduce their volume of crude oil purchases from Iran during this wind-down period", the Treasury noted.
The result is that sanctions will start to phase in quickly and could start to progressively cut Iranian exports within the next few months, assuming the sanctions are effective. Its production accounts for about 4 percent of the world's oil supplies. That world no longer exists.
The news agency Bloomberg, citing Amrita Sen, chief oil analyst at Energy Aspects Ltd., noted that the renewal of Iranian sanctions can drastically change the agenda for the upcoming OPEC meeting in June.
So the existing deal may technically remain in force while members ignore its output levels in practice. At the core of the United States sanctions is a threat to cut-off companies that deal with Iran or its companies from the United States banking system.