Should it succeed and Tehran's two million barrels a day be taken off the market, the cost of oil is likely to soar and cause a major headache for Trump domestically; the American public are known to be hostile to anything that increases the cost of filling up their cars.
Outside North America, looming US sanctions against major oil exporter Iran were the focus of attention. Last month, members of OPEC agreed to pump an additional 1 million barrels of crude daily, a move that should help contain prices.
Oil surged in the past two weeks as the US pushes allies to end imports of Iranian crude, disruptions persist in places like Libya and American crude inventories shrink. The United States under President Barack Obama led negotiations of that deal, but Trump has withdrawn from the agreement and is reimposing sanctions on those doing business with Iran.
"OPEC has not defined oil prices for the past 30 years", Kazempour said. The price of diesel fuel used largely by truckers was $3.17 a gallon, up 30 percent from a year ago, AAA said.
"Because it's driving season, you expect a lot of crude to go through refineries right now - so that's why we were looking for a draw", said Gene McGillian, vice president of market research at Tradition Energy in Stamford, Connecticut.
The state oil company, known as Saudi Aramco, cut pricing for a key crude grade to Asia, its biggest market. In late morning trading, the price of the worldwide benchmark Brent grade of crude oil was little changed at $77.85 a barrel. Iran's OPEC governor, Hossein Kazempour Ardebili, accused the United States and Saudi Arabia of trying to push up oil prices and said both countries are acting against the foundation of OPEC. But the tougher USA approach now makes the bank's analysts think that Iran's exports to Europe, Japan, and South Korea-a total of 1 million bpd-would "fall to minimal levels".
Futures closed just 0.3 per cent higher after surging past US$75 a barrel earlier in the session.
"If they want to stop Iranian oil exports, we will not allow any oil shipment to pass through the Strait of Hormuz", Ismail Kowsari, an Iranian Revolutionary Guards commander, told Iran's Young Journalists Club, Reuters reported.