US President Donald Trump on Friday blamed Canada for the spread of smoke from wildfires, and said he would contact Prime Minister Mark Carney to learn Ottawa's plans for dealing with the fires.

Trump wrote in a post on his Truth Social platform: 'The cost of this pollution should necessarily be added to the tariffs that Canada is currently paying.' He added: 'The United States is suffering an unjustified invasion of dirty, polluted, and unhealthy air, whose quality is dangerous and completely unacceptable.'

Thick clouds of smoke from wildfires, drifting south from Canada, triggered new warnings about deteriorating air quality in the United States on Friday, raising concerns about the World Cup final scheduled for Sunday near New York.

Air quality indices in Detroit and Chicago entered the 'hazardous' range, and the tracking site IQAir reported that they were the two most polluted cities in the world, according to Agence France-Presse.

The southward movement of winds also severely affected the capital Washington, which recorded the second highest level on the index within the 'very unhealthy' category, a stage in which authorities urge residents to avoid unnecessary outdoor activities.

Smoke from Canadian wildfires covers the Manhattan skyline (AFP)

In New York and neighboring New Jersey, where the final match will be held on Sunday in an open-air stadium, weather conditions became 'unhealthy,' after haze on Thursday made the Manhattan skyline barely visible.

Andrew Giuliani, executive director of the White House task force for the World Cup, said in a press briefing that tournament organizers are 'monitoring the situation closely.'

Experts at the National Weather Service warned that smoke could become denser overnight and into Saturday morning.

Expert Peter Mullinex of the service told AFP: 'What we will start to see is a return of northwesterly winds over the Great Lakes region, where these winds will carry some of that smoke and push it toward the Northeast region.'

But he clarified that forecasts do not indicate that air quality in the northeastern United States on Sunday will be as bad as what the region experienced during the week.

He added that during the match between Spain and Argentina, 'we do not expect to see the intense smoke density we are currently seeing,' even if hazy conditions persist. He continued: 'I don't think this will have the same impact that playing a match right now would have.'