The Justice Department and the Federal Trade Commission urged state attorneys general Friday to investigate potential gasoline price gouging and collusion among oil companies, escalating a pressure campaign President Donald Trump has waged against the industry as pump prices have lagged the recent plunge in crude costs.

Associate Attorney General Stanley Woodward Jr. and FTC Chair Andrew Ferguson told state law enforcers in a letter that the agencies are closely watching petroleum markets and that market volatility does not suspend antitrust or consumer protection laws.

Neither agency directly polices price gouging, the letter noted, but more than three dozen states, territories, and the District of Columbia have their own statutes barring exorbitant price increases during emergencies, and the agencies urged those states to consider enforcement.

Prices have stayed elevated since the U.S.-Iran war shut the Strait of Hormuz for more than three and a half months beginning in late February, choking off a waterway that normally carries about one-fifth of the world's oil.

The national average for a gallon of regular gasoline stood at $3.82 Friday, AAA data show, down from wartime highs but still well above the $2.98 average recorded the week before fighting began.

Trump has pressed oil companies over the pricing gap for more than a week.

In a Truth Social post on June 24, he wrote that oil companies were not lowering pump prices to match falling crude costs, saying customers were being "gouged" and that he had ordered the Justice Department to investigate.

He followed with a post Monday night demanding that "Gasoline Retailers must get their Prices down, IMMEDIATELY!" and pushing a target near $2.50 a gallon.

Oil executives have pushed back on the timeline.

Chevron Chief Financial Officer Eimear Bonner told CNBC's "Squawk Box Europe" this week that lower crude costs take time to reach the pump. "It's going to take time though," she said, pointing to a lag between falling crude prices and retail relief, and added that prices should ease as the market normalizes.

The letter also directs consumers to report suspected violations through the DOJ's Citizen Complaint Center and the FTC's fraud-reporting portal, adding a new layer of scrutiny as gas prices remain a pocketbook issue heading into November's midterm elections.