South Korea's Industry Ministry said on Monday it will respond to the looming 50% U.S. tariff on steel products as part of its trade discussions with Washington in order to minimise the impact on industry.

Iron ore fell to its lowest level since early May alongside equity markets after President Donald Trump said he would double tariffs on steel and aluminum to help protect American workers.

The so-called TACO trade will be tested as markets wait to see if Trump will actually follow through with his latest threat or if he will put it on hold soon.

President Trump would invoke other tariff authorities if his appeal of a trade court's ruling isn't successful, Commerce Secretary Lutnick said.

President Donald Trump is visiting a steel plant outside of Pittsburgh on Friday, where he is expected to tout a previously-announced deal between Japan's Nippon Steel Corporation and the United States Steel Corporation.

Hours after Elon Musk's farewell ceremony in the Oval Office, a U.S. appeals court denied the Trump administration's request to resume mass firings of federal employees. Meanwhile, President Trump returned to a key battleground state for a rally after declaring new steel tariffs and announcing a deal with Japan's Nippon Steel.

No matter the outcome of a major legal case on President Donald Trump’s tariffs, his import taxes are likely here to stay — in one form or another.