The threat follows complaints by US lawmakers over the wildfires and Ontario's premier Doug Ford asking the US to send support to fight the fires, rather than complain. "The United States is being unnecessarily invaded by filthy, polluted, and unhealthy air," Trump said, threatening to impose new levies over Canada's "willful negligence". As of Friday, there were about 888 fires actively burning in Canada, according to the Canadian Wildland Fire Information System - with the majority burning out of control. More than 190 of those blazes are burning in Ontario, some out of control. Trump said in his post to Truth Social that he would call Canadian Prime Minister Mark Carney to demand an explanation over his country's "willful negligence," accusing the country of "not properly maintaining" their forests and brush. Fellow Republicans have used the issue to renew Trump's call to make Canada the 51st US state, a musing that has offended Canadians and prompted many to stop travelling to their southern neighbour in protest. Others online suggested a delay in opening the Gordie Howe International Bridge, a Canada-funded project that will connect Ontario to Michigan. Carney noted that it was the responsibility of both countries to fight climate change. After Trump's remarks, Carney's emergency management cabinet minister said the two countries remain in constant contact and share a long history of working together on such disasters, citing a reciprocal fire-fighting agreement from 1982 and another assistance agreement  emerging from the 2025 G7 summit. Canada has worked to prevent wildfires and invested about CSD 12bn (USD 8.5bn; 6.4bn pounds) in forest sustainability and fire prevention, MP Eleanor Olszewski said in the statement. (BBC)