TOKYO (Kyodo) -- Nippon Steel Corp. CEO Eiji Hashimoto on Tuesday denounced U.S. President Joe Biden's decision to block its $14.1 billion acquisition of United States Steel Corp., saying he believes the order was politically motivated and reiterating that the company will seek to have it annulled in court.

"A review of the deal by the Committee on Foreign Investment in the United States was not properly conducted due to President Biden's illegal intervention," said Hashimoto, also the Nippon Steel chairman, at a press conference in Tokyo. "We can never accept this."

The remarks came a day after Nippon Steel said it filed a lawsuit seeking to nullify Biden's order. It argued the president "ignored the rule of law to gain favor with" the United Steelworkers union, which is a key supporter of his Democratic Party that has opposed the takeover by the Japanese company.

Hashimoto said the lawsuit will show Biden's decision was not made on national security grounds, despite his insistence to the contrary.

"There is a chance we can win," he said, adding that he is not considering any alternative to the current acquisition plan.

"We will never give up on growing our U.S. operations. There is neither a reason nor a need to," Hashimoto said, citing growing demand for high-grade steel used in electric vehicles and other applications. "This is the best way for us."

President-elect Donald Trump, who will take office on Jan. 20, has also publicly opposed the deal announced in December 2023 by Japan's biggest steelmaker and the smaller U.S. producer.

"Why would they want to sell U.S. Steel now when tariffs will make it a much more profitable and valuable company? Wouldn't it be nice to have U.S. Steel, once the greatest company in the world, lead the charge toward greatness again?" Trump posted on his Truth Social platform on Monday. "It can all happen very quickly!"

Hashimoto said the planned deal aligns with policies advocated by Trump as Nippon Steel's investment will strengthen U.S. manufacturing. He expressed hope that the incoming president will modify his stance on the takeover.

The Japanese company also sued rival Cleveland-Cliffs Inc., its CEO Lourenco Goncalves and United Steelworkers union leader David McCall in a separate suit, alleging they colluded to block the acquisition of U.S. Steel by any party other than Cleveland-Cliffs.

In a statement issued Monday, Goncalves called the lawsuit "completely baseless" and said, "Nippon Steel and U.S. Steel continue to play the blame game in a desperate attempt to distract from their own failures."

McCall also dismissed Nippon Steel's claim as groundless.

Japanese Foreign Minister Takeshi Iwaya and his U.S. counterpart Antony Blinken exchanged views on Nippon Steel's acquisition and confirmed the importance of bilateral commercial ties, including U.S. investments by Japanese firms, in a meeting in Tokyo on Tuesday, the Japanese Foreign Ministry said.