U.S. President Donald Trump's preliminary announcement Thursday that he will impose steep tariffs on imports of steel and aluminum was met with swift criticism from the Quebec government and key aluminum industry players in the province.

Trump said he would sign a document to impose tariffs of as much as 25 per cent on all steel imported into the U.S. and 10 per cent on all aluminum.

"It's, once again, a bad decision, an ill-advised decision from the Americans," said Quebec Premier Philippe Couillard.

The province produces the majority of Canada's aluminum and is a major supplier of aluminum to the U.S., and the aluminum industry accounts for nearly 30,000 Quebec jobs.

Still, Couillard said the move will harm the U.S. economy more than Quebec's: "Why? Because there's almost no aluminum production in the United States."

​Details on whether all countries, including Canada, will face the hefty tariffs have not yet been released.

As Canada is the main supplier to the U.S. of both steel and aluminum, the Trump administration has received multiple pleas to exempt it from the tariffs from organizations including the United Steelworkers Union, which has members on both sides of the border.

'It's the beginning of a potential trade war'

Quebec's aluminum industry has also been asking for exemptions after voicing concerns about the potential consequences on cross-border trade.

Jean Simard, the president and CEO of the Aluminium Association of Canada, said that if the U.S. government moves forward with the tariffs, it will mean "a long walk in the desert" for both Canada and Quebec.

"The U.S. is by far our most important and strategic market," he said, importing 90 per cent of Quebec's aluminum.

While Simard emphasized that the announcement is preliminary and not set in stone, he hopes the U.S. government will back down.

"This is a major issue," he said.

Jean Simard, the president and CEO of Aluminium Association of Canada, hopes that Canada will be exempt from the tariffs on aluminum and steel imports proposed by U.S. President Donald Trump. (CBC) "It's the beginning of a potential trade war, not only between Canada and the U.S., but the European countries and the U.S."

Alcoa, the aluminum company which has three aluminum smelters and employs 3,300 Quebecers, said Canada should be spared.

"We believe vital trading partners, including Canada, should be exempt from any tariff on aluminum," the company said in a statement.

"The aluminum industry has an integrated supply chain and actions should not penalize those that abide by the rules."