“The latest tariffs on steel and aluminum are unjustified, they’re illegal, they’re bad for American workers, bad for American industry and of course for Canadian industry as well,” Carney told reporters in Ottawa.

He vowed that Canada – the largest supplier of foreign steel and aluminum to the US – will “take some time, not much” to respond.

At the same time, the prime minister noted that “intensive discussions” continued with the US administration to rewrite Canada-US trade relations.

Doug Ford, the premier of Ontario province, which has a large number of steel producers, accused the Trump administration of breaking a “verbal agreement” not to escalate tariffs on Canadian metals.

That deal with US commerce secretary Howard Lutnick, he said, had been reached after Ford agreed to suspend a 25% surcharge on electricity exported to three American states.

“We can’t sit back and let President Trump steamroll us,” he said, adding that “everything’s on the table” in terms of retaliatory measures.

Canada exported 5.95 million tonnes of steel and 3.15 million tonnes of aluminum to the US last year, according to US government data.