TOKYO (Kyodo) -- Japanese Prime Minister Shigeru Ishiba warned Monday of potential repercussions for bilateral trade following U.S. President Joe Biden's decision to block a $14.1 billion acquisition of United States Steel Corp. by Nippon Steel Corp.

His remarks come as the Japanese steelmaker, the world's fourth-largest by production volume, prepares to file a lawsuit over Biden's decision, which was announced Friday. An executive said the company will hold a press conference on Tuesday.

Speaking at his first press conference of the year on Monday, Ishiba said he would seek clarification regarding the national security risk cited by Biden.

"Unfortunately, it is true that the Japanese business circles have voiced concern over future investments between Japan and the United States," Ishiba said. "We will have to take it very seriously."

In a statement issued Monday, Nippon Steel President Tadashi Imai said, "We will pursue every possible measure" as "we will never give up on expanding our U.S. operations," reiterating the firm's resolve to challenge Biden's decision.

Biden's order marked the first time a U.S. president has blocked a merger and acquisition deal involving a Japanese company. He said the takeover would "create risk for our national security and our critical supply chains."

Some analysts regard Biden's move as a political strategy to win support from the powerful United Steelworkers union, which has been a key supporter of his Democratic Party and has opposed Nippon Steel's takeover plan.

The outgoing president's decision has drawn criticism from the Japanese business community, with some insisting that he has set a bad precedent for other domestic firms pursuing acquisitions in the United States, a key ally of Japan.

In a joint statement released after the decision, Nippon Steel and U.S. Steel said U.S. authorities' review of their deal was "manipulated to advance President Biden's political agenda," and they will "take all appropriate action to protect our legal rights."

The two companies are expected to claim in court that Biden did not present sufficient evidence to prove the acquisition would pose a threat to U.S. national security and that his decision violated due process under the U.S. Constitution and a law governing the Committee on Foreign Investment in the United States.

The Washington Post reported Sunday that Biden's decision to block Nippon Steel's bid overrode the advice of numerous top aides, including Secretary of State Antony Blinken, U.S. Ambassador to Japan Rahm Emanuel and Treasury Secretary Janet Yellen, who argued against or expressed reservations about the president's position.

Japan's Economy, Trade and Industry Minister Yoji Muto also told reporters Monday that the president's decision is "extremely regrettable and hard to understand," adding the government will continue asking the Biden administration to clear concerns among the business communities in the two countries.

"Economic relations serve as the foundation of bilateral ties. I believe it is very crucial to develop an environment where companies can make investment decisions without concerns," Muto said.