President Trump turned his Twitter fire toward the world oil market Friday morning, accusing major members of the oil cartel who are currently meeting in Saudi Arabia of conspiring to keep the cost of petroleum artificially high.

“Looks like OPEC is at it again,” Trump said in his tweet, referring to the Organization of the Petroleum Exporting Countries. “With record amounts of Oil all over the place, including the fully loaded ships at sea, Oil prices are artificially Very High! No good and will not be accepted!”

Oil prices were wobbly following the president’s comments. Brent Crude was down a touch in midday trading before climbing back to $73.98. West Texas Intermediate was trading in the $68 range, and was up ever so slightly.

The president, whose tweets on trade and tariffs have shaken equity markets in recent weeks, made his remarks as major oil producers are gathering in Jeddah to update their cap on the amount of oil they pump from the ground.

The year-long strategy has successfully reduced worldwide oil inventories, tightening supply and demand enough to raise prices on oil exchanges from below $50 per barrel up to the vicinity of $70 per barrel.

The goal of OPEC, Russia and various non-OPEC producers is something akin to a Goldilocks scenario: keep oil prices high enough to fund their economies and create healthy profits but not so high that big consumers like the United States and Europe reduce demand.

“Oil prices are trying to find a comfort band that is somewhere above $50 a barrel and somewhere below $75 a barrel,” said Bob Tippee, editor of Oil & Gas Journal. “Producers want a comfortable level that is high enough for producers to be whole but it’s low enough not to be painful for gasoline consumers at the pump.”

The U.S. Energy Information Administration is forecasting higher prices for regular-grade gasoline at the pump for this summer’s driving season — from April through September — compared to 2017.

The EIA forecasts U.S. regular gasoline retail prices to average $2.74 per gallon, up from an average of $2.41 per gallon a year ago.

“The higher forecast gasoline prices are primarily the result of higher forecast crude oil prices,’ according to the EIA report. The annual hit to consumers would be about a $190 increase, or 9 percent more than what they spent in 2017.

Frank Verrastro, senior vice president at the Center for Strategic and International Studies, said the president is looking at oil prices through a political lens.

“We are entering the driving season and he doesn’t want American drivers before this fall’s election to see a bump in gas prices,” Verrastro said. “The president has an uncanny knack for redirecting stories. You don’t get penalized for blaming OPEC for higher gas prices … and the corresponding consumer ire.”

OPEC and its key non-OPEC ally, Russia, control nearly half of the world’s oil production. Their discipline to roll back production by more than 1.5 million barrels a day and keep it there has surprised the world.

“The discipline has been impressive,” Verrastro said. “Part of the reason is desperation. The fiscal positions of many exporting countries suffered tremendously because of the last price downturn.”

Saudi Arabia, for many years viewed as the swing producer because of its enormous production capacity, desires a firm oil price above $70 to fund its economic transformation and the planned public offering of its national oil company, known as Saudi Aramco. The Saudis hope to place about 5 percent of Saudi Aramco on public markets and receive the most optimal price to fund the kingdom’s needs.

But OPEC’s hold on world prices is less than what it was a decade ago because of U.S. advances in shale oil production, often through horizontal drilling and a production method known as “fracking.”

Shale oil drillers have spawned a revolution using high-pressure drilling, coupled with a mixture of water, sand and chemicals, which breaks open — “fractures” — hard-to-reach oil pockets trapped in rock.

U.S. crude oil production in recent months has flirted with record highs since the 1970s, thanks to the technological nimbleness of shale oil drillers. U.S. companies produce more than 10 million barrels a day of oil, which was considered unfathomable a decade ago. The United States, Russia and Saudi Arabia now produce one third of the world’s oil supply.

Even with those dominant producers, world oil prices rest on a delicate balance of dozens of suppliers across the globe. The U.S. production alone could not make up for a sudden drop in supply if a major producer like Venezuela, or even Libya or Nigeria, curtailed pumping.

“The potential for a sudden loss of a big chunk of production is always there,” Tippee said. “Venezuela. Angola. Libya yo-yos all over the place. The market would go haywire for a while if one of those producers went away. It has in the past.”

Read more: