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.

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.

Nippon Steel was standing firm on its proposed $15 billion acquisition of U.S. Steel, Chief Executive Eiji Hashimoto said Tuesday after President Joe Biden’s blocked the top Japanese steelmaker’s move.