Trump blames Canada for wildfire smoke choking US cities

US President Donald Trump on Friday blamed Canada for wildfire smoke blanketing large parts of the United States and threatened to add the costs of the pollution to tariffs on Canadian imports.

"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!" Trump wrote on his social media platform Truth Social.

He said he would call the Canadian prime minister later in the day "to find out what they are going to do about it."

Trump accused Canada of refusing "to engage in basic Forest Management and Debris Removal," calling it "Willful Negligence" that he said had become "a yearly occurrence, costing the United States Billions of Dollars."

He said the cost of the pollution "must of necessity be added to the Tariffs Canada is currently paying."

Trump's remarks came as smoke drifting south from large wildfires in Canada pushed Detroit, Chicago and Washington to the top of global rankings for air pollution in major cities.