Donald Trump’s increased tariffs on imported steel and aluminium from 25 to 50 per cent came into effect on Wednesday.

The US President announced an increase in tariffs on May 30, ratcheting up pressure on global steel producers and deepening his trade war.

“We are going to be imposing a 25% increase. We’re going to bring it from 25% to 50% – the tariffs on steel into the United States of America, which will even further secure the steel industry in the United States," he said at a rally in Pennsylvania.

Later, in a post on his social media platform Truth Social, Trump wrote, “It is my greatest honour to raise the Tariffs on steel and aluminium from 25% to 50%, effective Wednesday, June 4th. Our steel and aluminium industries are coming back like never before. This will be another BIG jolt of great news for our wonderful steel and aluminium workers."

The doubling of steel, aluminiuminum levies intensifies Trump’s global trade war and came just hours after he accused China of violating an agreement with the US to mutually roll back tariffs and trade restrictions for critical minerals.

Shares of steelmaker Cleveland-Cliffs Inc. surged 26 per cent after the market closed as investors bet the new levies will help its profits.

The announcement drew harsh reactions from US trading partners around the world.

Canada’s Chamber of Commerce quickly denounced the tariff hike as “antithetical to North American economic security."

“Unwinding the efficient, competitive and reliable cross-border supply chains like we have in steelaluminiumminum comes at a great cost to both countries," Candace Laing, president of the chamber, said in a statement.

Canada’s United Steelworkers union called the move a direct attack on Canadian industries and workers.

The European Commission said on Saturday that Europe is prepared to retaliate.

“This decision adds further uncertainty to the global economy and increases costs for consumers and businesses on both sides of the Atlantic," a European Commission spokesperson said.

“The EU is prepared to impose countermeasures, including in response to the latest US tariff increase."

Australia’s centre-left government also condemned the tariff increase, with Trade Minister Don Farrell calling it “unjustified and not the act of a friend."

The United States is the world’s largest steel importer, excluding the European Union, with a total of 26.2 million tons of imported steel in 2024, according to the Department of Commerce. As a result, the new tariffs will likely increase steel prices across the board, hitting industry and consumers alike.

Steel and aluminum tariffs were among the earliest put into effect by Trump when he returned to office in January.

The tariffs of 25 per cent on most steel and aluminum imported to the US went into effect in March, and he had briefly threatened a 50 per cent levy on Canadian steel but ultimately backed off.