President-elect Trump has also opposed Nippon Steel's $15 billion acquisition of U.S. Steel, which President Biden blocked last week.

The companies argued in a lawsuit announced on Monday that Biden violated the Constitution by blocking the merger via a sham national security review that deprived the companies of their right to a fair process.

President Joe Biden officially announced on Friday he has blocked Nippon Steel's $14.1 billion purchase of U.S. Steel, setting up a likely federal court battle.

U.S. Steel and Nippon Steel said on Monday that it is suing over President Joe Biden's decision to block its sales agreement and a domestic competitor and union over their actions to scuttle the deal.

President Joe Biden on Friday announced his decision to block the $14 billion sale of U.S. Steel to Japan’s Nippon Steel, citing national security concerns. The move could have serious implications in Gary,

Separate lawsuits from Nippon Steel and U.S. Steel target President Joe Biden as well as a steelworkers union head and a rival steelmaker’s CEO.

In dual lawsuits filed Jan. 6, U.S. Steel Corp. and Nippon Steel Corp. blame the Biden administration's politicizing its national-security review as well as the behind-the-scenes actions by rival Cleveland-Cliffs Inc. and United Steelworkers International President David McCall for scuttling the $14.9 billion deal.

Nippon Steel Corp. and U.S. Steel filed federal lawsuits Monday challenging the Biden administration’s decision as ignoring “the rule of law.”

Overturning Mr Biden’s decision in court will be tough. Judges give wide latitude to the executive on matters of national security, and allegations of insufficient due process will be a hard sell, says Jonathan Gafni of Linklaters, a law firm.

The CEO of Nippon Steel says he will not give up on the company's push to acquire US Steel, after the bid was blocked by US President Joe Biden last week. The companies are now suing the US government to reverse the decision.

U.S. Treasury Secretary Janet Yellen said on Wednesday that Nippon Steel's planned acquisition of U.S. Steel received a "thorough analysis" by an interagency review body that was sent to President Joe Biden,