Nippon Steel has faced an uphill battle in its bid to buy US Steel. US President Donald Trump's comments over the weekend suggest it may need to reconsider plans to make the American firm its fully owned subsidiary.

Trump said Sunday that nobody could hold a majority stake in US Steel. This followed his earlier comments saying Nippon Steel needed to make "big investments" in order to get the deal done.

The Japanese government weighed in on the issue. Chief Cabinet Secretary Hayashi Yoshimasa said on Monday, "We are aware that Nippon Steel is not looking at the case as a mere acquisition, but is considering a bold proposal that is completely different from anything it has done in the past." He added that it would create a "win-win situation for both countries" through significant investments and high-quality products.

Trump has indicated that he will meet Nippon Steel executives this week. The company said its Chairman and CEO, Hashimoto Eiji, is ready to fly to Washington to meet with the president, if invited.

Nippon Steel announced a plan in 2023 to acquire all shares of US Steel and make it a wholly owned subsidiary. It said it would be difficult to provide highly confidential, state-of-the-art technology to the firm otherwise.