EU officials were also working to develop potential incentives to persuade Tehran to stick with the deal despite the USA withdrawal, including by making financing available through the European Investment Bank. Estimates vary from little impact anticipated by Barclays Plc, to a potential loss of more than 50 percent of the country's 2.7 million barrels of daily shipments predicted by consultant FGE.
Meanwhile, West Texas Intermediate crude for June delivery gained 70 cents to hit $71.84 per barrel at 7.41 a.m. London time on the NYMEX.
Primary sanctions restrict USA companies from doing business with Iran.
On currency markets, the dollar held around its 2018 highs against the euro following a recent run of below-par data out of the eurozone that has fed speculation the European Central Bank may have to put on the back burner plans to wind in its crisis-era stimulus.
The Europeans will also have to persuade European companies that have gone back into business in Iran that they should not abandon those deals out of fear of being penalized or even losing access to the much larger and more lucrative US market.
Since the Iran nuclear deal went into effect, its exports have risen to about 2.5 million bpd, from less than 1 million bpd. Sales to Europe are seen by analysts as the more likely to be reduced by the sanctions.
In addition, current trade tensions between China and the United States mean that Beijing is unlikely to support USA action against Iran.
Events affecting Iran, prompted by the May 8 decision of US President Donald Trump to withdraw America from a 2015 nuclear deal, may appear irrelevant to Caribbean countries. The state's junior U.S. Senator Tom Cotton is chief among the champions of the President's move. They will grumble and accept it.More news: U.S. jets intercept pair of Russian bombers off Alaskan coast
"It is absolutely incumbent upon our government to do everything we can to make sure Americans are not left behind, and that we bring the Americans who are detained there home, that we find Robert Levinson and bring him home", Sherman said during a call with reporters arranged by the group National Security Action.
"The Iranian oil sanctions during the Obama era reduced Iranian crude oil production by 1 million barrels per day", Chris Lafakis, an energy economist for Moody's Analytics, said in a statement, according to Bloomberg. "As before, it may take several rounds of reductions to reach target levels", FGE's founder and chairman Fereidun Fesharaki wrote in a note.
Saudi Arabia is ready to offset any supply shortage but it will not act alone to fill the gap, an OPEC source familiar with the kingdom's oil thinking said on Wednesday.
Yesterday, India had said that all the parties concerned should engage constructively to resolve the Iranian nuclear issue peacefully.
Iran's top three rivals say its development of more powerful, longer-range ballistic missiles and its backing of majority-Shiite Muslim groups overseas are destabilizing to the Middle East. Saudi Arabia is now battling an insurgent Yemeni Zaidi Shiite Muslim group-also known as the Houthis or Ansar Allah-who occasionally targets Riyadh with missiles that Saudi Arabia claims are Iranian in origin.
Nearly immediately after Trump's announcement, Saudi officials began to signal their willingness to make up for any shortfall in global oil supply caused by US restrictions. With that, what will Iran do now that sanctions are being imposed again, and what will OPEC do, if anything, given anticipated changes in Iranian oil exports?
Both contracts notched their biggest daily percentage gain in a month. The agency has raised its forecasts every month since last August.
China remained the largest export destination for Iranian oil, with flows rising to 714,467 b/d in April, up just over 20,000 b/d from March.