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

The suit, filed in the U.S. Court of Appeals for the District of Columbia, alleges that it was a political decision and violated the companies’ due process.

U.S. Steel and Japan’s Nippon Steel sued the United States government on Monday in a last-ditch attempt to revive their attempted merger after President Biden blocked it last week on the basis that the transaction posed a threat to national security.