Brent crude, the international benchmark for oil prices, hit $80 per barrel on Thursday as market analysts are concerned about the aftermath of the U.S. leaving the Iran nuclear deal. The highest price since November 2014 comes as Iranian exports are expected to fall, reducing supply in an already tightening market.

The Trump Administration is giving companies 90 to 180 days to wind down current business with Iran subject to wide-ranging sanctions. The market is becoming convinced that Trump will be able to disrupt crude exports after the White House slapped sanctions on the head of Iran’s central bank earlier this week said John Kilduff, founding partner at energy hedge fund Again Capital.

“That showed that he’s not kidding around. It’s very much a forward-leaning, aggressive strategy against Iran,” he said.

The President has taken a remarkably tougher stance than many expected, restoring all sanctions that were in place prior to their suspension in 2016.

Nevertheless, the market debate still lingers over the effectiveness of the sanctions, considering that China and U.S. allies in Europe still support the nuclear deal. While some analysts claim U.S. sanctions could wipe one million barrels per day of Iranian crude off the market, others said the impact would be limited to fewer than 500,000 barrels a day.

Kilduff said that although EU nations are looking at different avenues to protect European energy companies, the worldwide oil market is shaky on their determination if the Trump Administration will issue sanction waivers to shippers, insurers, and financial institutions necessary to bring Iranian oil to buyers.

“It’s not clear right now, but it’s becoming clearer that they will have a problem and oil will be coming off the market,” Kilduff said.

On Wednesday, France’s Total S.A., a multinational oil and gas conglomerate, warned it might abandon a multibillion-dollar gas project in Iran if it could not secure a waiver from U.S. sanctions, meaning even more doubt places on European-led efforts to salvage the now defunct nuclear deal.

Meanwhile, the U.S. is fast-approaching the summer driving season, when refineries draw down oil inventories to meet increased demand at the gas pump. Higher oil prices are now providing an incentive for U.S. drillers to pump more crude, raising expectations for U.S. oil output growth for 2018 to increase by at least 120,000 barrels a day.

On this mark, West Texas Intermediate crude fell 24 cents to $71.25 a barrel, according to a report from CNBC. U.S. oil output is closing in on 11 million barrels of oil per day, and drillers are quickly closing in on top oil producer Russia, which pumps just over 11 million barrels a day.