Speaking alongside Japanese Prime Minister Shigeru Ishiba at the White House, Trump said Nippon would instead “invest heavily” in the company without taking a majority stake.

The Japanese firm’s attempted takeover of Pennsylvania-based US Steel was previously blocked by President Joe Biden on national security grounds.

Union members and Trump had repeatedly criticised such a merger, which would have created one of the biggest steel companies in the world.

No details of the agreement were shared at Friday’s bilateral, and Nippon has long stressed its plans to invest in the company.

Trump – who mistakenly referred to the firm as “Nissan” – said he would meet Nippon’s head next week to “mediate and arbitrate” the deal.

Facing political pressure, the Biden administration blocked the purchase on the grounds that domestic ownership was important.

The Japanese government had called Biden’s decision “incomprehensible” and both Nippon and US Steel ultimately filed a lawsuit.

More recently, Nippon has argued that the purchase would be “in line” with Trump’s focus on manufacturing, job creation and promoting investment in the US.

Prime Minister Ishiba was in Washington to cement ties with the country’s primary foreign partner.

Both US and Japanese officials said the main purpose of the visit, however, was to forge a personal relationship with Trump – who had a warm relationship with former premier Shinzo Abe during his first term.

The visit marks the first by an Asian leader to the White House since Trump’s second administration began in January.

It is the second by a foreign leader during the new administration, following Israeli Prime Minister Benjamin Netanyahu’s trip earlier this week.

“On television, he is very frightening,” Ishiba told reporters of Trump at Friday’s joint news conference.

“But when I met with him, he was very sincere. And very powerful. And of very strong will.”

During Trump’s first term from 2017-21, he grew close to Shinzo Abe, bonding over golf. Abe resigned in 2020 and was assassinated two years later.

Japanese officials said Ishiba made “every possible preparation” for his meeting with Trump, including seeking advice from Abe’s widow – who attended the inauguration as a guest of Melania Trump – and from his predecessor, Fumio Kishida.

Ishiba also underscored Japan’s role as a major economic partner for the US, and highlighted that Japan has been the top foreign investor in the US for five consecutive years.

Among multinational firms, Japanese companies are the largest job creators in 10 states and the second largest in another six.

In Kentucky alone, Japanese companies employ more than 45,000 people, primarily in auto equipment manufacturing.

Earlier in the day, Trump said that while tariffs against Japan could still be possible, he believes the $68bn US trade deficit with Japan can be addressed and would be “very easy” for Japan.

“We have a fantastic relationship,” he said. I don’t think we’ll have any problem. They want fairness also.”

Asked about the possibility of US tariffs – and counter-tariffs – Ishiba declined to provide details.

“I am unable to respond to a theoretical question,” he said, eliciting laughs from Trump and journalists in the room. “That’s the official answer we have.”

A White House announcement of his executive order cited “credible evidence” that the firm “might take action that threatens to impair the national security of the United States”.

Biden decided to block the deal despite intense efforts to sway him in recent days by some of his senior advisors, who reportedly warned that rejecting a sizable investment from a top Japanese corporation like Nippon Steel could damage Washington’s relations with Tokyo.

BBC News has contacted Nippon Steel and US Steel for comment.

The decision was left with the outgoing President Biden after a US government panel failed to reach a consensus in late December on whether the acquisition by Nippon Steel may threaten Washington’s national security.

Biden was legally required to act within a 15-day deadline, after the deadlock by the Committee on Foreign Investment in the United States (CFIUS).

He has repeatedly criticised the deal, joining other US politicians who have called the transaction into question.

They include President-elect Donald Trump and the incoming vice-president, JD Vance.

The deal became caught up in the 2024 US presidential campaign when Pennsylvania emerged as a critical swing state and leaders of the United Steelworkers union loudly opposed it.

Nippon Steel has previously described the transaction as a lifeline to Pennsylvania’s much-diminished steel industry in the past.

The Japanese company and US Steel have also previously suggested they may pursue legal action against the government if the deal did not happen.