Canada is escalating its response to President Donald Trump's trade war, with another round of retaliatory tariffs set to take effect September 8.

But two key Canadian exports — oil and potash, a key fertilizer ingredient — should stay out of the fight, one Canadian premier said Wednesday.

"What we as a province cannot and will not support is any kind of export tariff on our natural resources or any of our resources that are being exported to the US or through the US to other areas of the world," said Scott Moe, the premier of Saskatchewan in Western Canada, at a press briefing.

His warning comes as the US-Canada trade fight escalates.

Trade negotiations broke down last week, and new 50% US tariffs on about $20 billion of Canadian imports took effect Saturday. On Monday, Trump threatened to raise tariffs on Canadian-made vehicles, auto parts, and steel to 50% beginning January 1, 2027.

Canada is planning for dollar-for-dollar retaliation beginning September 8. On Tuesday, the country announced tariffs on 27.6 billion Canadian dollars, or about $20 billion, of US imports, including steel, dairy, and electronics.

Canadian leaders have increasingly been looking for leverage over the US, from reconsidering F-35 purchases and targeting US coal shipments to raising the possibility of cutting off electricity exports.

Moe said he supports Ottawa's targeted countertariffs, provided they limit the damage at home.

"We are supportive of these very targeted countermeasures," he said, provided they have "a minimal impact on Canadian industries and families" and a larger effect on the US.

But taxing potash exports would backfire by costing Canadian jobs and pushing US buyers toward other suppliers, he said.

Canada is the world's largest potash exporter, accounting for about 40% of global exports in 2024, according to data from the Canadian government. The US received 53% of Canada's potash shipments that year.

Oil is another red line for Moe.

"We cannot in any way support the adding of export tariffs on a product like oil," he said, calling such a move "an unsustainable hit to our Canadian economy."

The White House exempted energy and potash from its latest 50% tariffs.

Moe said he has not heard Ottawa propose export tariffs on either commodity.

He warned against retaliatory measures that might feel satisfying but ultimately hurt Canada's interests.

"We should be very careful with respect to policies that maybe make us feel good at the moment," Moe said, arguing that the focus should instead be on measures that help get the US back to the negotiating table.

Saskatchewan is retaliating elsewhere. Starting September 8, the province will impose a 50% levy on American alcohol while continuing to sell US booze.

Canada is one of the US's largest trading partners, with about $870 billion in goods and services traded between the two countries in 2025.