Canadian Prime Minister Mark Carney accused the United States on Saturday of making a last-minute "power play" aimed at restricting Canada's ability to pursue trade agreements with other countries, offering new details about what he said caused negotiations between the two nations to collapse.

According to Carney, the U.S. introduced new demands in the final hours of the talks, touching on Canada's other trading relationships, its auto sector, and protections for Canadian culture and the French language.

"The U.S. introduced at the last hours, in the last hour, efforts to restrict our ability to have other trade deals," Carney told reporters.

Asked what he believed the U.S. was trying to accomplish, Carney replied: "It's a power play. It's a power play and, you know, [it] becomes a question of sovereignty."

Negotiations suspended as tariffs take effect

The comments came one day after Carney suspended negotiations and ordered Canada's trade team back to Ottawa, as President Donald Trump's 50% tariffs on roughly $28 billion in Canadian goods took effect. Trump has framed his tariff campaign against Canada in part as a response to fentanyl trafficking, an argument Ottawa rejects by pointing to U.S. border data showing that only a small fraction of fentanyl seizures occur at the northern border. The escalation weighs on one of the world's largest trading relationships, with two-way commerce between the two countries running at well over $1 trillion a year.

Canada has said it plans to match the U.S. tariffs dollar for dollar, extending a pattern from earlier rounds this year, when Ottawa imposed counter-tariffs on tens of billions of dollars in U.S. goods in response to American steel, aluminum and fentanyl-linked measures. Carney said Saturday that the retaliation will target sectors including steel, dairy, appliances, agricultural equipment, pulp and paper, and electronics. The measures are scheduled to take effect the Tuesday after Labor Day, Sept. 8.

Washington disputes Carney's account

Washington has disputed Carney's version of why the negotiations broke down. U.S. Trade Representative Jamieson Greer said Friday that Canada declined to finalize terms agreed to earlier in the week, accusing Ottawa of making new demands and walking back previous commitments.

"Tonight [Friday], Canada declined to finalize the trade deal under the terms agreed earlier this week," Greer said in a statement. "Despite the U.S. offer to Canada to receive the best treatment of any major exporter to our market, new demands and walk backs of other commitments by Canada have upended the careful balance reached in the past days."

Greer said the U.S. had offered Canada significant tariff reductions on steel, aluminum, autos and lumber, along with a broader economic and national security partnership covering digital trade, critical minerals, aerospace and export controls.

Carney offered a different account on Saturday.

"In short, they asked too much, and they offered too little," he said.

Autos and cultural protections at issue

Autos represented another major sticking point. Carney said the two sides disagreed over tariff levels, the treatment of Canadian content, and which vehicles would be covered by a potential agreement. The sector is particularly exposed because North American auto supply chains are deeply integrated under the U.S.-Mexico-Canada Agreement, with components often crossing the border several times before a finished vehicle is assembled — and the trilateral pact itself faces a scheduled joint review in 2026, another deadline hovering over any bilateral settlement.

He said the U.S. also continued to press for changes involving Canada's protections for its culture and the French language — changes Carney said Ottawa would not accept. Canada has long carved its cultural industries out of trade agreements, a protection carried through from the original NAFTA into the USMCA, while French-language protections in Quebec are enforced under provincial law.

The breakdown came just days after Trump paused the 50% tariffs for three days and announced that the U.S. and Canada had, subject to final documentation, reached a "DEAL!" Carney said Saturday that the two sides had made significant progress before the negotiations unraveled.

Support for affected businesses

Canada is now preparing additional support for businesses affected by the tariffs, particularly small and medium-sized companies. Carney said the government will release details of that support alongside its retaliatory measures — the next scheduled milestone in a dispute that has lent urgency to his push, since taking office in March, to diversify Canadian trade toward Europe and Asia and reduce dependence on the U.S. market. Whether the two sides return to the table before the Sept. 8 measures take effect remains an open question, with Washington and Ottawa offering directly conflicting accounts of who upended the talks.

Asked whether the latest escalation amounted to a full-scale trade war, Carney said Canada was responding to an attack.

"We're attacked. Like you're at war when you get attacked, we got attacked," Carney said.

"We've got the reserves. We've got resilience. We have the plan. We get the focus. We respond. We're going to focus on what we can control. We are going to build."