Canada will give a “firm and clear” response to the latest trade barriers planned by US President Donald Trump, says Prime Minister Justin Trudeau.

Trump says he will levy a 25% import tax on all steel and aluminium products entering the US from 12 March, meaning both sides have a month to negotiate. Canada is the top exporter of both metals to the US.

Since returning to office last month, Trump has announced a wide range of these tariffs to try to protect US jobs and industries. Economists say they are likely to raise prices for ordinary Americans.

The new tariffs were “entirely unjustified”, Trudeau said, as Canada found itself in a second trade standoff with Washington in a matter of weeks.

Canada was “the US’s closest ally”, he added.

A range of metal-exporting countries are scrambling to make a deal in response to the tariff on steel and aluminium vowed by Trump.

The US imports six million tonnes of Canadian steel products and more than three million tonnes of aluminium products per year – more than from any other country.

Canadian metal exports were making North America as a whole “more competitive and secure”, Canadian Industry Minister François-Philippe Champagne argued on Monday.

Canadian provincial leaders, too, have condemned Trump’s plan. Quebec’s François Legault said his province alone sent millions of tonnes of aluminium to the US per year – asking whether Trump would prefer to source the metal from his rival, China.

Federal official opposition leader, Pierre Poilievre, said he would issue matching tariffs targeting the US, if elected as Canadian prime minister.

The head of the Canadian Steel Producers Association warned that a range of sectors could be hit, saying similar measures by Trump during his first term had damaged industry in both countries.

“We have steel that they need and they have steel that we need… we need each other,” Catherine Cobden told CBC.