The Justice Department and Federal Trade Commission on Thursday sent a letter to state attorneys general urging them to investigate businesses engaging in price gouging in retail gasoline sales. 

In a Truth Social post last month, President Donald Trump pointed to falling oil prices and claimed that gas prices should immediately drop as well. Since gasoline prices remain high, he alleged, large oil companies are engaging in anticompetitive behavior. 

"The big Oil Companies are not dropping their price at the pump commensurate with the sharply lower prices they are paying for Oil. Those prices are dropping like a rock! In other words, customers are being 'gouged,'" Trump said, adding that he was directing the DOJ to investigate. 

In their letter, the FTC and DOJ explain that antitrust laws "govern the trade of oil and fuel no differently than any other market" and directed state attorneys general to "use all tools available" under their state laws to "investigate and prosecute any misconduct causing unjustified price increases." 

"Companies and individuals who seek to unlawfully exploit our nation’s citizens will face federal investigation, civil liability, and criminal prosecution," the letter warns.