Smoke from wildfires in Canada and Minnesota covered skies across the United States on Friday, causing air quality deterioration in large areas of the Great Lakes, the Northeast, and Mid-Atlantic states.

This comes as fires continue to burn out of control, while US President Donald Trump threatened Canada with tariffs over what he called 'poor forest management'.

The thick smoke covered the sky of the US capital Washington with a dark and unfamiliar foggy layer, and the city's famous landmarks disappeared, leading to the postponement of a baseball game between the Cleveland Guardians and the Pittsburgh Pirates in Ohio, according to the Associated Press.

Warnings of dangerous conditions are expected to continue until Saturday in large areas of the United States, despite a possible temporary improvement with forecast thunderstorms in some affected areas over the weekend.

Smoke to persist for days as fires continue to burn

According to the Associated Press, Bob Oravik, chief meteorologist at the US National Weather Service in Maryland, warned that the improvement might be temporary over the weekend, stressing that the smoke will not disappear soon as the fires continue to burn largely out of control.

He said: 'The source of the smoke will definitely continue for a week, and possibly longer,' explaining that its impact will depend on wind direction and where the smoke clouds drift.

Wildfires

Fires are burning in Canada's Ontario province as well as areas in Minnesota, which US authorities closed while firefighting efforts continue.

Communities in Minnesota, Illinois, and Michigan, including Detroit, recorded some of the worst air quality levels in the world on Friday, according to IQAir, a website specializing in air quality monitoring.

Washington was also heavily affected, as orange-tinted fog covered the Washington Monument, the Lincoln Memorial, and other national landmarks for much of the day.

US President Donald Trump criticized Canada, blaming it for the crisis over what he called poor forest management, and threatened to impose additional tariffs on the country.

Hundreds of fires are burning in Canada, including about 190 in northern Ontario, according to provincial Premier Doug Ford, while flames destroyed the indigenous community of Namaygoosisagagan, and forced 10 areas in northern Ontario to evacuate or prepare for evacuation.

The increase in wildfires in Canada's vast forests is largely attributed to the effects of climate change.

Improvement expected before World Cup final

Weather conditions raised concerns about the impact of smoke on the World Cup final on Sunday between Spain and Argentina at MetLife Stadium in New Jersey.

Oravik said winds would continue to push the fire smoke east across the United States, but he expected conditions to be better on game day compared to Saturday.

Authorities in New York, New Jersey, Pennsylvania, and other northeastern states distributed K95 masks for free, canceled outdoor events, and opened libraries and public buildings as clean air shelters.

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