The fight over US Steel is intensifying, and a top competitor now wants in

• One of US Steel's rivals has entered the fight over the steelmaker's sale.
• US Steel threatened to close its mills if Biden blocked its sale to Japan's Nippon Steel.
• Now Cleveland-Cliffs is offering to buy US Steel's unionized mills if it follows through on its threat.

As the fight over US Steel ramped up this week, its top US steelmaking competitor condemned the company and offered to save the day.

Cleveland-Cliffs, a steel manufacturer based in Cleveland, said in a press release Thursday that it would support President Joe Biden's reported decision to block the $14.9 billion sale of the Pittsburgh-based US Steel to the Japanese steelmaker Nippon.

Biden has not announced that he will formally block the deal — which US Steel and Nippon agreed to in December — but sources told both The Washington Post and the Financial Times earlier this week that the president planned to do so soon.

Just hours before Biden's planned rejection was reported, US Steel suggested that it would close down its mills and move out of Pennsylvania — a swing state critical to the 2024 election — if the deal collapsed.

Then, Cleveland-Cliffs entered the chat.

In its press release, the Ohio company offered to buy up US Steel's unionized mills if it followed through on its threat to close them down.

"Cleveland-Cliffs stands ready to immediately acquire and invest in any and all union-represented assets that US Steel shuts down, protecting union jobs and investing in the future livelihoods and communities in which the facilities operate," Cleveland-Cliffs CEO Lourenco Goncalves said in the release, adding that the company had the support of the United Steelworkers union and ample financing available.

And the company didn't waste the opportunity to throw shade at its rival.

"The last-minute threats by US Steel to shut down integrated steelmaking production, fire union workers, and move their headquarters from Pittsburgh if their deal does not close is just a pathetic blackmail attempt on the United States government and the Commonwealth of Pennsylvania," Goncalves said. "By taking immediate action, our government is showing that this type of shameless behavior will never be tolerated."

Goncalves said the steel mills should remain American-owned and -operated — a stance that Vice President Kamala Harris and former President Donald Trump have echoed on the campaign trail.

US Steel has maintained that the sale to Nippon would not affect national security.

The company's CEO, David Burritt, has also defended the possibility of shuttering its mills, telling The Wall Street Journal that the company just didn't "have the money" to keep them open.