Nippon Steel Chief Executive Eiji Hashimoto says the top Japanese steelmaker is standing firm on its proposed $15 billion acquisition of U.S. Steel.

President Joe Biden decided to block the $14 billion takeover of US Steel by Japan’s Nippon Steel even though some top US officials did not believe there were sufficient national security grounds to kill the deal,

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.