Donald Trump has launched an explosive rant against Canada – threatening to double tariffs as part of an ongoing trade war. The US president said his tirade was connected to “Ontario, Canada, placing a 25% tariff on ‘electricity’ coming into the United States.”

He continued: “I have instructed my secretary of commerce to add an additional 25% tariff, to 50%, on all steel and aluminium coming into the United States from Canada, one of the highest tariffing nations anywhere in the world. This will go into effect tomorrow morning, March 12. Also, Canada must immediately drop their anti-American farmer tariff of 250% to 390% on various US dairy products, which has long been considered outrageous.”

The US president declared a “national emergency” for the electricity supply in the area that had been “threatened” by Canada.

He continued: “This will allow the US to quickly do what had to be done to alleviate this abusive threat from Canada. If other egregious, long-time tariffs are not likewise dropped by Canada, I will substantially increase, on April 2, the tariffs on cars coming into the US, which will, essentially, permanently shut down the automobile manufacturing business in Canada.”

The US leader repeated his solution for Canada to become part of the US – a form of taunting that has infuriated Canadian leaders.

“The only thing that makes sense is for Canada to become our cherished 51st state,” Mr Trump posted on Tuesday. “This would make all tariffs, and everything else, totally disappear.”

Mr Trump made a series of bold claims, which have yet to be verified, including that the US “subsidises Canada to the tune of more than $200bn a year”.

He concluded: “Canadians’ taxes will be very substantially reduced, they will become more secure, militarily and otherwise, than ever before, there would no longer be a northern border problem, and the greatest and most powerful nation in the world will be bigger, better and stronger than ever … and Canada will be a big part of that.”

Mr Trump said his plans to make Canada a US state would make what he described as the “artificial line of separation” along the border “finally disappear”.

Over the weekend, Doug Ford, Ontario’s premier and leader of Canada’s most populous province, announced it was charging 25% more for electricity to 1.5million American homes and businesses in response to Mr Trump’s trade war.

Ontario provides electricity to Minnesota, New York and Michigan. Mr Ford said his province would hit back against the US trade taxes.

At a press conference, he said: “I will not hesitate to increase this charge. If the United States escalates, I will not hesitate to shut the electricity off completely.

“Believe me when I say I do not want to do this. I feel terrible for the American people who didn’t start this trade war. It’s one person who is responsible, it’s President Trump.”