Commerce Secretary Wilbur Ross fired back at Canadian Prime Minister Justin Trudeau on Saturday, calling Canada's trade threats "inappropriate."

"We continue to believe that a negotiated settlement is in the best interests of all parties and we are prepared to work toward that end," Ross said in a statement obtained by Reuters.

"Threats of retaliatory action are inappropriate and will not influence any final determinations," he added.

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A day earlier, Trudeau said in a letter to the premier of British Columbia that he was seriously considering banning U.S. firms from exporting thermal coal from ports in the Pacific coastal province.

The threat came 10 days after the Trump administration tariffs of up to 24 percent on Canadian softwood lumber exports to the U.S.

Lumber producers in the U.S. have long complained that Canadian producers receive government subsidies, lowering the price of lumber produced in Canada.

Reuters also reported that Canada is considering tariffs on exports from Oregon, including wine, plywood and flooring. Such a move would be a jab at Sen. Ron Wyden Ronald (Ron) Lee WydenGOP senator blocks Schumer resolution aimed at Biden probe as tensions run high Republican Senators raise concerns over Oracle-TikTok deal Hillicon Valley: TikTok, Oracle seek Trump's approval as clock winds down | Hackers arrested for allegedly defacing U.S. websites after death of Iranian general | 400K people register to vote on Snapchat MORE (D-Ore.), who has advocated for the lumber duties.

As a candidate and in his first months in office, President Trump has assailed international trade agreements as unfair toward the U.S. and has threatened to negotiate the deals or withdraw the U.S. completely.

That threat and the dispute over the softwood lumber tariffs has eroded U.S.-Canada trade relations recently.

Trump threatened last week to withdraw from the North American Free Trade Agreement – the deal between the U.S., Canada and Mexico – but ultimately backed away from that position.