OTTAWA, July 17 - President Donald Trump on Friday blamed Canada for wildfire smoke spreading across the United States and said he would add the "incalculable cost" of dealing with the pollution to existing tariffs on Canadian goods.

Heavy smoke from hundreds of Canadian fires enveloped a swath of the U.S. from the Midwest to the Northeast on Thursday and Friday, prompting warnings to residents to stay indoors.

Trump, who has a combative relationship with Prime Minister Mark Carney, said he would be calling the Canadian leader to find out what he planned to do about the "totally unacceptable" situation.

"We are holding Canada responsible for the fact that they are not properly maintaining their Forests ... and the United States is being unnecessarily invaded by filthy, polluted, and unhealthy air," he said in a Truth Social post.

"This is Willful Negligence, and becoming a yearly occurrence, costing the United States Billions of Dollars, which cost of this pollution must of necessity be added to the TARIFFS Canada is currently paying."

Canada's minister of emergency management and community resilience, Eleanor Olszewski, said the government has invested C$12 billion ($8.56 billion) in forest sustainability and fire prevention since 2020 as the country faces increasingly drier, warmer weather.

She also cited a long history of U.S.-Canadian partnership in fighting wildfires on both sides of their border.

"At this time, our first priority is protecting Canadians and keeping communities safe," Olszewski said in a statement.

Climate experts say rising temperatures have led to drier timber and more wildfires in recent years in Canada, home to some of the world's largest forest landscapes.

"As our climate warms, we're seeing ... more extreme weather, and we're going to see more fire," said Mike Flannigan, a professor of wildland fire at Thompson Rivers University in British Columbia.

Shortly after taking office in 2025, Trum...