ST. LOUIS—A handful of U.S. Senators, including Josh Hawley of Missouri, are calling on the Biden administration to reject Nippon Steel’s $14.1 billion takeover of U.S. Steel saying Biden’s public statements urging U.S. Steel to remain domestically owned and operated have not gone far enough.

U.S. Steel is a major employer in the greater St. Louis region. The company’s Granite City Works temporarily laid off 1000 workers when it idled a blast furnace last fall, but currently employs roughly 850 union steelworkers.

In March, President Biden came out in opposition to the merger.

“U.S. Steel has been an iconic American steel company for more than a century, and it is vital for it to remain an American steel company that is domestically owned and operated,” he said in March.

But in a Thursday letter to the president, Hawley and fellow Republican Senators Marco Rubio of Florida and JD Vance of Ohio, said the administration needs to go further.

“By law you possess the authority to block the sale of U.S. Steel unilaterally under the Defense Production Act,” they wrote. “Pronouncements about what you consider “vital” or what you think “should” happen to U.S. Steel are worthless unless you act to keep U.S. Steel under American control.”

Vance and Rubio are believed to be among those under consideration to be former President Donald Trump’s running mate in November. The letter points out that Trump has already said publicly that he would block the sale.

“The ability to produce our own steel in this country is a national security issue. I mean have we learned nothing from COVID, has Biden learned nothing…We found out during COVID that my gosh, our critical supply chains, they’re all overseas. Our medical supply chains. They’re overseas,” Hawley told Spectrum News Thursday. “If Japan is allowed to buy U.S. Steel and control our steel production in this country, take away our steel jobs, I mean how can we be a sovereign nation?”

Nippon Steel has pledged to maintain existing labor agreements, but the United Steelworkers Union has come out against the deal. The President of United Steelworkers Local 1899 in Granite City could not be reached for comment Thursday.

Lucas Kunce, a leading Democratic candidate to face Hawley in November’s general election, has said he opposes the sale of U.S. firms in strategic industries to any foreign entity.

A spokesperson for Rep. Nikki Budzinski, D-Ill, who represents Granite City in Congress, said Thursday the congresswoman strongly supports the ongoing reviews by Justice department and The Committee on Foreign Investment in the United States. “She’s continuing to work closely with the Steelworkers to push for the best possible path forward for the Granite City Works plant,” the spokesperson said.

Nippon Steel said last week that it expects the deal to close by December, a delay of three months, after the Department of Justice requested more information.

More than 98% U.S. Steel Corp. shareholders voted at a special investor meeting in April to approve the takeover. The U.S. Steel name and an American headquarters in Pittsburgh would remain after the deal.