If the U.S. even partially succeeds in its aggressive plan to halt Iranian oil exports, world crude supplies will become tighter, sending oil and fuel prices higher for consumers and businesses.

A senior State Department official Tuesday said the U.S. is seeking a reduction in Iranian exports to zero and does not intend to grant any waivers for companies or countries seeking exemptions. President Donald Trump pulled the U.S. out of the Iran nuclear deal, which continues to be supported by Iran and the other parties to it: the U.K., Germany, Russia, China, Italy and France.

Even with the addition of barrels promised by OPEC and other producers last weekend, the world market is down hundreds of thousands of barrels because of Venezuela's production issues and a surprise outage in Canada, which took 360,000 barrels off the market last week.

There was also the sudden loss of 450,000 barrels a day in Libya, a still unclear situation. The leader of Libya’s eastern political faction has transferred control of ports to a parallel national oil company aligned with his faction. The existing national oil company does not recognize that new company.

“If that is the position the administration chooses to pursue, it could create a very tight oil market and cause even another revisiting of the OPEC and Vienna alliance supply management decision,” said Carlos Pascual, IHS Markit senior vice president and former State Department energy envoy during the first round of sanctions on Iran.

Oil prices shot higher on Tuesday after the State Department's comment, with Brent up about 2 percent to more than $76 per barrel and West Texas Intermediate up 3.5 percent at $70.46 per barrel. Many analysts have expected the U.S. to be able to halt about 500,000 barrels a day of Iranian exports, but some said Tuesday with the strident tone of the Trump administration and lack of waivers, that number could now be higher.

“We already raised our number to 700,000 for Q4,” said Helima Croft, head of global commodities research at RBC. “Could that number now top a million? Yes. Certainly I think the losses will ‎pass the million mark in Q1 2019 if the State Department sticks to this strategy. Europe, South Korea and Japan will comply. India will likely at least partially comply. China is the wild card.“

Iran exports about 2.4 million barrels a day, and the U.S. and other nations succeeded in keeping about half that amount from the market the last time Iran was sanctioned. But this time the U.S. is acting alone, as the six other countries remain committed to the deal to curb Iran’s nuclear program in exchange for an end to financial sanctions.

Trump has complained the Iran deal was one-sided and would not be in place long enough, meaning Iran could return to its nuclear program at some point.

“I think [the sanctions] will be a pressure point on prices. What we’re seeing is more and more buyers of Iranian crude that are stopping buying, and this is going to accelerate,” said Edward Morse, head of global commodities research at Citigroup.

For instance, Total CEO Patrick Pouyanne said last week that his company, which has actual deals in Iran, would end plans to develop one of the world’s largest natural gas fields for fear of secondary sanctions from the U.S. Simply put, the U.S. sanctions mean if an entity has business with Iran it cannot deal with the U.S. financial system.

India’s state bank has warned refiners there will be no financing for Iranian oil, but China, the largest importer, has not taken a position. In the last round of sanctions, China continued to buy oil from Iran, using a company that dealt with a bank with no connection to the U.S. banking system.

“Technically, Iran can export to China and use renminbi, and Iran can use renminbi to buy things from China,” Morse said. He expects the U.S. sanctions to remove 800,000 to 1 million barrels of Iranian crude from the market.

The U.S. has also looked to Saudi Arabia, the world’s largest exporter, to add more oil to support the market as Iranian sanctions hit. Saudi Arabia and the rest of OPEC, along with Russia and other producers agreed last week to add 1 million barrels a day to the market. Saudi Arabia has already been ramping up production and is expected to pump record amounts, possibly as much as 11 million barrels a day during the summer season, when Saudi consumes more oil domestically for power generation, Morse said.

He expects the price of Brent to average $75 per barrel in the third quarter and $79 in the fourth quarter.

Gasoline futures also rose Tuesday, jumping to $2.06 a gallon, and prices at the pump averaged $2.84 a gallon Tuesday, about 12 cents less than Memorial Day, according to AAA.

Gasoline prices may have reached their peak for the summer, barring an unexpected outage or sharp spike in oil prices, analysts said. As the Nov. 4 date for the sanctions approaches, gasoline normally would not be rising. However, if there is strict compliance with sanctions, analysts say prices could jump and drive heating oil and fuel prices higher for everyone from weekend drivers to operators of cruise ships, airlines and trucking firms.

“The timing of the election could complicate the situation for the administration, if supplies suddenly get real tight,” said John Kilduff, partner at Again Capital. The U.S. midterm election is Nov. 6.

Morse said the world has spare capacity that can be tapped and refining demand will drop after the summer. Canada’s outage should be over, and he said Russia could add more barrels to the market beyond what it will restore as part of the OPEC deal. He also said production could be restarted in the neutral zone, which is between Saudi Arabia and Kuwait and operated by both.

But others are concerned it will be hard to meet demand because of various outages, including the continuing deterioration of Venezuela's industry, which could result in the loss of 750,000 barrels a day this year alone.

“We’re still in deficit, and the lost Iranian barrels will push even deeper. We’re consuming more than is being supplied by the market,” said Kilduff. He said major producers have been providing less oil than the world uses, but world supply was met by the glut of oil that has been in storage.

That oversupply has been whittled down. Oil in storage is at a more normal level and even slightly below its five-year average. In the U.S., for instance, the hub at Cushing, Oklahoma, has also been oversupplied, but now those inventories are near multiyear lows.

Global oil demand is just under 100 million barrels a day, and just about 4 percent of that is produced by Iran. During the spring, OPEC was supplying about a third of world oil, according to the International Energy Agency.