President Donald Trump has announced the US will double its current tariff rate on steel and aluminium imports from 25% to 50%, starting on Wednesday.
Speaking at a rally in Pittsburgh, Pennsylvania, Trump said the move would help boost the local steel industry and national supply, while reducing reliance on China.
Trump also said that $14bn would be invested in the area's steel production through a partnership between US Steel and Japan's Nippon Steel, though he later told reporters he had yet to see or approve the final deal.
The announcement is the latest turn in Trump's rollercoaster approach to tariffs since re-entering office in January.
"There will be no layoffs and no outsourcing whatsoever, and every US steelworker will soon receive a well-deserved $5,000 bonus," Trump told the crowd, filled with steelworkers, to raucous applause.
One of the major concerns from steelworkers about the US-Japan trade deal was how Japan would honour the workers' union contract which regulates pay and hiring.
Trump began his remarks by saying he had "saved" US Steel, America's biggest steel manufacturer, located in Pittsburgh, with the 25% tariffs he implemented during his first term as president in 2018.
He touted the increase to 50% as a way to ensure US Steel's survival.
"At 50%, they can no longer get over the fence," he said. "We are once again going to put Pennsylvania steel into the backbone of America, like never before."
US steel manufacturing has been declining in recent years, and China, India and Japan have pulled away as the world's top producers. Roughly a quarter of all steel used in the US is imported, and the country's reliance on Mexican and Canadian steel has angered Trump.
The announcement comes amid a court battle over the legality of some of Trump's global tariffs, which an appeals court has allowed to continue after the Court of International Trade ordered the administration to halt the taxes.
His tariffs on steel and aluminium were untouched by the lawsuit.
"It is a good day for steelworkers," JoJo Burgess, a member of the local United Steelworkers union who was at Trump's rally, told the BBC.
Mr Burgess, who is also the city mayor of nearby Washington, Pennsylvania, expressed optimism over the reported details of the partnership with Nippon Steel, saying he hoped it would help breed a new generation of steel workers in the area.
He recalled "making a lot of money" in the years after Trump instituted steel tariffs in his first term.
Although Burgess would not label himself a Trump supporter, and says he has only voted for Democratic nominees for president in the last two decades, he said: "I'm never going to disagree with something that's going to level the playing field for American manufacturing."
But so far the impacts of Trump's tariffs have largely led to global economic chaos. Global trade and markets have been upended and cracks have formed - or widened - in relations between the US and other countries, including some of its closest partners.
The levies have strained relations between China and the US, the world's two biggest global economies, and launched the countries into a tit-for-tat trade battle.
On Friday, without providing details, Trump accused China of violating a truce they had reached over tariffs earlier this month over talks in Geneva.
US Trade Representative Jamieson Greer later clarified that China had not been removing non-tariff barriers as agreed under the deal.
China then shot back with its own accusations of US wrongdoing. Beijing's response on Friday did not address the US claims directly but urged the US to "cease discriminatory restrictions against China".
China is the world's largest manufacturer of steel, responsible for more than half of global steel production, according to World Steel Association statistics from 2022.
"If you don't have steel, you don't have a country. You don't have a country, you can't make a military. What are we going to do? Say, 'Let's go to China to get our steel from the army tanks,'" Trump quipped at the Pittsburgh rally on Friday.
Trump's roughly hour-long, wide-ranging rally speech hinted at the deal he said he had made with Japan's Nippon Steel but he did not offer any new details. Both companies have not confirmed any deal was completed.
While campaigning for president, Trump had said he would block foreign acquisition of US Steel, the storied 124-year-old American steel company. It is unclear how the reported partnership would operate and who would own the company.
White House officials said Trump had convinced Japan's Nippon Steel to boost its investment in the US and give the government key say over the operations of the US factories.
According to US media, Japan plans to invest $14bn over 14 months.
Other reported details include that the companies had said they would maintain ownership of US steel in the US, with US citizens on the board and in leadership positions; pledged not to cut production for 10 years; and agreed to give the government the right to veto potential production cuts after that period.
