U.S. Steel and Nippon Steel of Japan filed a lawsuit Monday against the U.S. government over President Biden’s decision to block their $14.3 merger.

The two companies alleged Biden’s actions were motivated by “purely political reasons.”

“Today’s legal actions demonstrate Nippon Steel’s and U. S. Steel’s continued commitment to completing the Transaction – despite political interference,” the companies said in a statement.

On Friday, Biden issued an executive order to halt the transaction saying Nippon’s acquisition of U.S. Steel would place America’s largest steel producers under foreign control and create a “national security” risk.

In a statement on Friday, Biden said "a strong domestically owned and operated steel industry represents an essential national security priority and is critical for resilient supply chains."  

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"That is because steel powers our country: our infrastructure, our auto industry, and our defense industrial base," he said. "Without domestic steel production and domestic steel workers, our nation is less strong and less secure."The lawsuit in the U.S. Court of Appeals for the District of Columbia alleges that the Biden administration “ignored the rule of law” and rejected the merger to curry favor with the United Steelworkers (USW) labor union.

The companies also alleged that the Committee of Foreign Investment in the United States, a federal interagency committee, which reviewed the transaction, was “deeply corrupted by politics, and the outcome was pre-determined” to satisfy the political objectives of the Biden White House.

White House spokesperson Robyn Patterson responded to the lawsuit Monday by reiterating Biden's stance.

"A committee of national security and trade experts determined this acquisition would create risk for American national security," Patterson told USA TODAY in a statement. "President Biden will never hesitate to protect the security of this nation, its infrastructure, and the resilience of its supply chains.”

At the end of 2023, Japan was the top foreign investor in the U.S, investing $783.3 billion, according to the Bureau of Economic Analysis.

“It is shocking − and deeply troubling − that the U.S. government would reject a procompetitive transaction that advances U.S. interests and treat an ally like Japan in this way,” the companies said in a statement after Biden’s announcement.

The companies petitioned the court to set aside Biden’s order and instruct CIFIUS to conduct a new review.

The companies also filed a second lawsuit against rival steel company Cleveland-Cliffs, its CEO Lourenco Goncalves and Dave McCall, president of the United Steelworkers labor union (USW) for colluding to block the transaction.

The lawsuit alleged they had engaged in a “coordinated series of anticompetitive and racketeering activities” illegally designed to prevent “any party other than Cliffs from acquiring U. S. Steel.”

Swapna Venugopal Ramaswamy is a White House Correspondent for USA TODAY. You can follow her on X @SwapnaVenugopal