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

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.

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.

By blocking a Japanese company’s takeover of U.S. Steel, President Joe Biden says he is protecting good jobs in the American heartland

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.

The companies condemned the president's decision and hinted at taking legal action, while U.S. Steel's CEO accused Biden of "political corruption."

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 Biden blocked the deal between Nippon and U.S. Steel earlier this month due to "national security" concerns.

The steel companies allege White House decision to block takeover was political and violated their right to due process.

U.S. Steel and the Japanese firm that had sought to acquire it are suing the Biden administration after the president announced he was blocking a proposed deal for the iconic American manufacturer.

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.

The acquisition was controversial as some argued foreign ownership over one of America's largest steel producers posed a threat to national security. Now, U.S. Steel's stock is taking a hit.