OTTAWA — Canadian Prime Minister Mark Carney announced retaliatory tariffs on the United States on Saturday, after walking away from what he called a "bad deal" on trade in a deepening rift between the longtime allies.

Carney, who led both the Bank of Canada and the Bank of England before entering politics, took office in March and won an April election in which his handling of the U.S. relationship featured prominently.

Negotiations between the neighboring countries broke down Friday in Washington, allowing new 50-percent U.S. tariffs to enter into force. The duties cover roughly $20 billion worth of goods, equivalent to 5.5 percent of Canadian exports to the United States, and apply to products ranging from hockey sticks to cement. The 50 percent rate, announced by Trump in mid-August, came with a lower 10 percent levy on Canadian energy.

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

U.S. President Donald Trump hit back at Canada on Sunday, declaring on Truth Social: "Canada wants the benefits of being a State, without being one!!!"

"They have also charged our great farmers, for many years, massive amounts of Tariffs. No more!!!" he added.

Carney said the new Canadian tariffs will notably target the U.S. steel and dairy industries and take effect on Sept. 8, with further details to be announced next week. Canada is the largest foreign supplier of steel and aluminum to the United States, while its dairy sector operates under a supply-management system of quotas and over-quota tariffs that exceed 200 percent on some products and have long drawn complaints from American producers.

Trump had previously said Washington "should be able to have a deal with Canada," citing his "good relationship" with Carney. But on Saturday, Canada's prime minister said Trump had set conditions that ultimately proved unacceptable, even though earlier talks had been positive.

"In recent days, the United States proposed new terms that were uneconomic, unfair and undermined the net benefits for Canada, and called into question the reliability of any deal," Carney said in Ottawa. "We cannot accept what they've offered, and we will not give what they've asked."

What Washington says it offered

U.S. Trade Representative Jamieson Greer told the New York Times on Saturday that the United States had offered to reduce its tariffs on steel, aluminum and autos, and to eliminate a recently imposed tariff on Canadian lumber. Greer said those measures would have given Canada "the most preferential treatment of any trading partner," according to the Times.

Speaking to Fox News on Saturday, Greer said Washington was "moving forward with measures that respond to Canadian retaliation," adding that no new talks were planned with Canadian negotiators. A senior U.S. official characterized this week's talks in Washington as candid and not acrimonious.

'Significant pressure'

Canada has been seeking relief from Trump's tariffs on autos, steel and aluminum — duties that have battered the country's economy, forced job losses and strained what was once an iron-clad trade relationship. The White House had alleged "discriminatory treatment" by Canada against U.S. alcohol, automobile and dairy products in introducing the duties.

The dispute stretches back to February, when Washington first levied tariffs on Canadian goods citing fentanyl and border concerns, then added duties on steel and aluminum — moves that prompted Ottawa to impose counter-tariffs on tens of billions of dollars' worth of U.S. products.

The tariffs were originally set to take effect on Wednesday, before Trump issued a three-day reprieve, citing progress in the talks.

Carney said one reason the deal collapsed was that U.S. negotiators introduced, at the 11th hour, restrictions on Canadian trade deals with other countries. He said the U.S. side also made unacceptable "threats" to the French language and "Quebec culture," referring to the French-speaking province in eastern Canada.

The escalating trade war drew anger from Democratic lawmakers and governors of border states including Minnesota, New York and Washington, who blamed Trump for triggering chaos that will raise costs for U.S. businesses and families. Canada is the top export customer for most U.S. states.

"Needlessly picking fights with our allies and raising prices here at home. That's Trump's economic policy in a nutshell," New York Gov. Kathy Hochul posted on X.

Beyond the latest tariffs, the United States and Canada still have to agree on revisions to the North American free trade agreement, USMCA, which replaced NAFTA in 2020 and is scheduled for a joint review in 2026. Trump's threats to make Canada the 51st U.S. state have also antagonized Canadians, including during Carney's May visit to the White House, where the prime minister told him Canada was "not for sale."

'Written in pencil'

Carney has repeatedly said relations with the United States have been forever altered, and that Canada must reduce its reliance on its southern neighbor, which currently accounts for roughly 70 percent of Canadian exports. His government has already moved to widen other channels, reaching a renewed trade agreement with the United Kingdom in July and pressing the European Union to move ahead with full ratification of its trade pact with Canada.

"We've been under no illusions. We recognized from the start that America has changed," Carney said Saturday. "We recognize that sometimes, its signature was written in pencil."

The prime minister spoke with provincial leaders to outline next steps. One of them, Ontario Premier Doug Ford, said Canadians must remain united.

Trump "can't be trusted, simple as that," Ford told reporters. "President Trump is the type of person who would steal your lunch money."

The Business Roundtable, a group of 200 chief executives of leading U.S. corporations, warned that the new tariffs "risk raising costs for American businesses and families," and urged both governments to resume negotiations.