Trump signed two proclamations that levied a 25 percent tariff on steel and a 10 percent tariff on aluminium imported from all countries except neighbouring Canada and Mexico.
US President Donald Trump today imposed heafty tariffs on imported steel and aluminium, citing national security concerns and the need to protect American industries from "unfair" business practices, triggering fears of a global trade war.
Trump signed two proclamations that levied a 25 percent tariff on steel and a 10 percent tariff on aluminium imported from all countries except neighbouring Canada and Mexico. The contentious tariffs will go into effect in 15 days.
Other countries would have to negotiate with US Trade Representatives (USTR) if they want exemptions from the steel and aluminium import tariffs.
Trump, who was surrounded by steel and aluminum workers at a White House event, said strong steel and aluminium industries were vital to the US national security.
"Absolutely vital. Steel is steel. You don't have steel. You don't have a country. Our industries have been targeted for years and years. Decades, in fact, by unfair foreign trade practices, leading to the shuttered plants and mills, the laying-off of millions of workers, and the decimation of entire communities. That's going to stop," he said.
Trump said the "unfair" foreign trade practices were not merely an "economic disaster" but a "security disaster" and by signing the two proclamations he was defending America's national security.
"We want to build our ships, we want to build our planes, we want to build our military equipment with steel, with aluminium from our country. And now we're finally taking action to correct this long-overdue problem. It's a travesty," he said.
Trump said he wants a lot of steel coming to the US, but asserted that it should be "fair".
"We want our workers to be protected and we want, frankly, our companies to be protected. By contrast, we will not place any new tax on product made in the US. So there's no tax if a product is made in the USA. You don't want to pay tax? Bring your plant to the USA. There's no tax," he said.
The action being taken, the president said, follows a nine-month investigation by the Department of Commerce, documenting a growing crisis in US steel and aluminium production that threatens the security of the country. It is also bad for US economically and with jobs, he rued.
Trump called the "aggressive" foreign trade practices an "assault on our country".
"The American steel and aluminium industry has been ravaged by aggressive foreign trade practices," he said.
Trump's surprise announcement has already spooked markets, caused a rift with his closest allies on Capitol Hill, and prompted the resignation of his top economist Gary Cohn.
America's top trading partners, the European Union and China have already warned of retaliation.
Major nations reacted sharply to Trump's decision to impose tariffs on steel and aluminum imports, warning of damage to close relations amid industry calls for retaliation.
Japan said the move would have a "big impact" on the countries' close bilateral ties, while China said it was "resolutely opposed" to the decision and South Korea said it may file a complaint to the World Trade Organisation.
China described Trump's decision as a "serious attack" on the system of international trade.
EU Trade Commissioner Cecilia Malmstroem tweeted that, as a close ally of the US, the bloc should be excluded from the tariffs.
The UK government said it would work with EU partners to consider "the scope for exemptions" while "robustly" supporting UK industries.
French Economy Minister Bruno Le Maire said there were "only losers" in a trade war.
Trump also pledged to impose "reciprocal tax" on countries like China and India if they do not match America's tariff.
"We're going to be doing a reciprocal tax programme, at some point so that if China is going to charge us 25 percent or if India is going to charge us 75 percent and we charge them nothing. They are 50, they are 75 or they are 25, we are going to be doing the same numbers. It's called reciprocal. It's a mirror of tags. So they charge us 50, we would charge them 50," Trump said before signing the two proclamations.
Trump in recent weeks had complained India's tariff on the import of high-end American motorcycles - specifically Harley-Davidsons - was too high."They will charge us 50, we charge them nothing. Doesn't work. So that's called a reciprocal tax ... mirror attacks. We will be going to be doing a lot of them," Trump said.