President Donald Trump on Friday accused Canada of "willful negligence" in forest management, blaming the country for wildfire smoke drifting into the United States.
In a social media post, Trump said the U.S. is being "unnecessarily invaded by filthy, polluted, and unhealthy air" due to Canada's failure to maintain its forests and brush.
The president said he planned to call Canadian Prime Minister Mark Carney later in the day to discuss the issue and seek action.
Trump argued that Canada has refused to engage in basic forest management and debris removal despite knowing such practices could reduce the risk of devastating wildfires.
He claimed the recurring problem costs the United States billions of dollars and insisted those costs "must of necessity be added to the TARIFFS Canada is currently paying."
The president did not explain how such costs would be incorporated into existing tariffs or whether formal trade action would follow.
The remarks come as smoke from nearly 850 active wildfires in Canada, including more than 180 in Ontario, has reached the United States.
Air quality alerts have been issued in more than 20 states from the Upper Midwest to the Northeast.
Health officials warn that wildfire smoke poses risks to people with heart or lung conditions and advise residents to monitor air quality and limit outdoor activity when conditions worsen.
