WASHINGTON (AP) —  President Donald Trump on Friday accused foreign-owned meat packers of driving up the price of beef in the U.S. and asked the Department of Justice to open an investigation.

The Republican president announced the move on social media days after his party suffered losses in key elections in which the winning Democratic candidates focused relentlessly on the public’s concerns about the cost of living.

“I have asked the DOJ to immediately begin an investigation into the Meat Packing Companies who are driving up the price of Beef through Illicit Collusion, Price Fixing, and Price Manipulation,” Trump wrote in the social media post.

“We will always protect our American Ranchers, and they are being blamed for what is being done by Majority Foreign Owned Meat Packers, who artificially inflate prices, and jeopardize the security of our Nation’s food supply,” he continued.

Trump offered no proof to support his allegations.

“Action must be taken immediately to protect Consumers, combat Illegal Monopolies, and ensure these Corporations are not criminally profiting at the expense of the American People,” he said.

Last month, Trump suggested the U.S. would buy Argentine beef to bring down stubbornly high prices for American consumers, angering U.S. cattle ranchers.

Beef prices have soared in part after drought and years of low prices led to the smallest U.S. herd size in decades. Trump’s tariffs on Brazil, a major beef exporter, have also curbed imports.

Trump’s accusations have renewed a bipartisan presidential fight against rising food prices.

Then-President Joe Biden talked with independent farmers and ranchers about initiatives to reduce food prices by increasing competition within the meat industry. And then-Vice President Kamala Harris, who Trump defeated in winning reelection last year, used her campaign to vow to crackdown on food producers and major supermarkets “ price gouging.”