U.S. Steel will close mills and likely move its headquarters outside Pittsburgh if a $14.9 billion buyout deal by Nippon Steel falls through, the Wall Street Journal reported Wednesday, citing an interview with the company’s CEO.

The steelmaker’s CEO David Burritt told the WSJ that Nippon has committed to investing nearly $3 billion in U.S. Steel’s older mills, which is crucial to maintaining competitiveness and keeping workers in jobs.

“We wouldn’t have done it if the deal had fallen through,” Burritt told the WSJ. “I don’t have the money.”

The deal was announced in December and has since come under increasing criticism from US politicians and the United Steelworkers union.

On Tuesday, Democratic presidential candidate Kamala Harris said U.S. Steel should remain in domestic hands, while Republican candidate Donald Trump said he would block the deal if elected.

US Steel and Nippon Steel have tried to allay concerns about the deal and touted its benefits.

Earlier on Wednesday, Nippon said that if the deal goes through, the U.S. company’s core management team and a majority of its board members would be U.S. citizens.

Burritt told the WSJ that the expanded Arkansas plant would allow the company to close Mon Valley, its last steelmaking operation in Pittsburgh. The company would likely look to move its headquarters south.

The transaction has received all non-U.S. regulatory approvals and the green light from U.S. Steel shareholders. It is currently subject to regulatory review in the United States.