OTTAWA — Wildfires burning across northwestern Ontario forced additional evacuations and kept air quality warnings in place on Friday, as thick smoke disrupted rail traffic and grounded outdoor activity across the region. Environment and Climate Change Canada issued special air quality statements covering communities including Thunder Bay and Sioux Lookout.

The Ontario Ministry of Natural Resources reported dozens of active fires in the province's northwest, several classified as out of control. Several First Nations communities had begun moving vulnerable residents, with the Canadian Red Cross assisting relocation efforts to Thunder Bay and southern centres.

Canadian National Railway confirmed that smoke and fire activity had disrupted freight movements along key corridors linking western Canada to Ontario ports. The company said crews were monitoring track conditions and that some services faced delays.

Via Rail also warned passengers of possible schedule changes on routes through the affected region. The smoke pushed air quality readings into high-risk categories across parts of Ontario and drifted south into Manitoba and the northern United States.

Health authorities advised residents with respiratory conditions to remain indoors. The fires add to a punishing wildfire season that has strained Canada's firefighting resources and prompted appeals for interprovincial and international assistance.

Prime Minister Mark Carney's government has faced repeated pressure to expand federal support for fire-hit communities. The Canadian Interagency Forest Fire Centre said crews from other provinces had been deployed to bolster Ontario's response.