Tokyo, Japan - Nippon Steel will make a "bold proposal" in its effort to invest in US Steel, Japan's top government spokesperson said Monday, after President Donald Trump hinted that he would consider letting take a minority stake in the American firm.

Former president Joe Biden blocked the $14.9 billion deal shortly before he left office last month, citing national security grounds, sparking a joint lawsuit from the firms – and condemnation from Japanese Prime Minister Shigeru Ishiba.

Trump, who met Ishiba Friday at the White House, said the companies will "be looking at an investment rather than a purchase".

On Sunday, the president, who heavily criticized the takeover offer during his 2024 presidential election campaign, said he would allow "investments" in the company.

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"Nobody can have a majority stake [in] US Steel. They can for other companies, but not for US Steel," Trump told reporters. "But they are allowed to invest in it, and that's different."

He said his team would see Nippon Steel executives "to mediate and arbitrate."

On Monday, Japanese Chief Cabinet Secretary Yoshimasa Hayashi told a regular news briefing: "We understand that Nippon Steel is not looking at this as a mere acquisition.

"But it is considering a bold proposal that is completely different from what we have seen in the past so that... it will produce superior products that the United States and the rest of the world want and create a win-win situation for both the US and Japan."

He did not provide details. Nippon Steel declined to comment on Trump's remarks.