A simmering trade rift between President Donald Trump and Canadian officials burst into the open Monday as Ontario premier Doug Ford sharply escalated his attacks on the president amid a widening tariff fight between the longtime allies.

"He can kiss my a– as far as I’m concerned. We’re going to go at him full steam, and we buy 400% more cars than anyone in the world," Ford said in an interview with Toronto radio station Newstalk 1010 Monday in response to Trump’s threat of new tariffs on Canadian autos, auto parts and steel.

Trump mocked Ford on Monday as "less charismatic, intelligent, and overall unimpressive" than his late brother, former Toronto Mayor Rob Ford, who became embroiled in a major 2013 scandal over his use of crack cocaine, which he later admitted.

The Ontario premier, dubbed "Captain Canada," has since emerged as one of the country’s most outspoken critics of Trump’s trade threats.

TRUMP TRADE CHIEF WARNS CANADA WALKED AWAY FROM 'THE BEST DEAL' TO TRIGGER 50% U.S. TARIFFS

The tariff fight is unfolding on two tracks: new 50% U.S. tariffs on certain Canadian goods took effect Aug. 22, with Canada set to retaliate Sept. 8, while Trump separately threatened to raise tariffs on Canadian autos and auto parts to 50% beginning Jan. 1, 2027.

The White House referred Fox News Digital to Trump’s Truth Social posts when approached for additional comment. 

"America has been carrying Canada for decades, but no longer! The U.S.A. will always be far bigger, richer, and stronger than Canada. Without the United States, Canada couldn’t survive — It’s where they get all of their money and, because of their current bad leadership, primarily Governor Carney, and his Flunky, Ford, they will not be allowed to keep taking advantage of the United States — Their key to survival," Trump added in a post.

TRUMP MUST CLOSE THE BACK DOOR CHINA USES TO EXPLOIT NORTH AMERICAN TRADE

He claimed Canada imposes tariffs of 400% or more on U.S. farmers and said he plans to end what he describes as unfair trade treatment of American companies and producers. Trump also threatened further economic pressure, claiming much of the electricity, oil and gas Canada receives is transported through the U.S. and calling on the country to "fall in line."

CANADA REPORTEDLY SCRAPS JOINT BRIDGE CELEBRATION WITH US AFTER TRUMP RENEWS TARIFF THREAT

Beyond tariffs, Trump also escalated the rhetoric Tuesday by floating a proposal to rename Lake Ontario "Lake America."

The current tariff fight traces back to late 2024, when Trump threatened 25% tariffs on Canadian goods and later joked during a meeting with then-Prime Minister Justin Trudeau that Canada could become the 51st state.

Fox News Digital reached out to Ford for comment.