President Trump on Friday threatened additional tariffs on Canada for wildfires that have blanketed large parts of the Midwest and East Coast in smoke in recent days, blaming the U.S.’ northern neighbor for failing to contain the blazes.

“We are holding Canada responsible for the fact that they are not properly maintaining their Forests, and Brush therein, and the United States is being unnecessarily invaded by filthy, polluted, and unhealthy air, the quality of which is dangerous, and totally unacceptable!” the president wrote on Truth Social, accusing Canada of “Willful Negligence.”

He went on to write that the problem is “costing the United States Billions of Dollars, which cost of this pollution must of necessity be added to the TARIFFS Canada is currently paying.”

Mr. Trump said he would discuss the matter with Canadian Prime Minister Mark Carney.

Asked about the president’s comments, Carney’s office referred CBS News to a statement from Canadian Minister of Emergency Management Eleanor Olszewski that said the country is “working with urgency alongside provincial and territorial partners.” She also said Canada has spent billions of dollars on forest fire prevention in recent years.

“Canada and the United States have a long history of working together to fight wildfires on both sides of the border — it is a history that both countries benefit from and that we are building on during this challenging wildfire season,” Olszewski wrote in her statement, pointing to Canadian firefighters’ role in assisting with last year’s Los Angeles wildfires.

Earlier this week, U.S. Ambassador to Canada Pete Hoekstra also praised the “outstanding cooperation between the United States and Canada” in fighting the “shared challenge” of wildfires. On Friday, Hoekstra shared Mr. Trump’s social media post criticizing Canada. 

Mr. Trump has had a tense relationship with Canada due to trade, NATO, a dispute over a Detroit-area bridge and Mr. Trump’s threats to make Canada the U.S.’ 51st state.

The Trump administration’s tariffs on goods from Canada — the second-largest U.S. trading partner — currently stand at 10%, though most Canadian imports are exempt because they comply with the U.S.-Mexico-Canada Agreement, a trade deal signed during Mr. Trump’s first term. The president’s ability to levy tariffs was constrained by a Supreme Court ruling earlier this year that blocked him from using an economic emergency powers law. 

Mr. Trump’s latest broadside against Canada comes as hundreds of wildfires burn there, causing smoke to blow into the New York City, Chicago, Detroit and D.C. areas, leading to severe air quality issues. Wildfires are also burning in Minnesota.

Some GOP lawmakers have blamed the Canadian government. Four Michigan Republicans penned a letter to Carney this week that said “our patience has run out,” accusing Canada of “chronic under-investment in forest thinning, fuel reduction, and prescribed burns.”

“This is the third consecutive year we have had to write to Canadian officials about a crisis that Canada has the tools to prevent and has chosen not to,” said Reps. John James, Lisa McClain, John Moolenaar and Jack Bergman, adding: “Our constituents are breathing the consequences of this failure right now, and they deserve better than to be told, again, that it will be handled.”

GOP Sen. Bernie Moreno of Ohio floated sanctions against Canada. And Republican Rep. Nick Langworthy of upstate New York wrote on X that “there should be consequences” if Canada fails to take “meaningful action” to prevent future wildfires. 

Carney briefly addressed the lawmakers’ criticism on Thursday by noting the role of climate change in extreme weather and chiding the United States for backing away from clean energy.

“Fighting climate change is the responsibility of all countries, including the United States,” Carney told reporters.

Ontario Premier Doug Ford, whose province is battling out-of-control wildfires, was more direct.

“I truly believe the Americans are good neighbors,” he said Friday. “If there’s some politicians out there chirping away, well, maybe what you should do rather than complain is send support, send help, because we have done the exact same thing for our American friends.”