President Trump walks along the Ellipse as he arrives at Marine One near the White House on Friday. Graham Hughes/NurPhoto via Getty Images hide caption toggle caption Graham Hughes/NurPhoto via Getty Images Canadian Prime Minister Mark Carney says his country will initiate retaliatory tariffs against American imports starting September 8. The move came hours after the Trump administration began imposing 50% tariffs on a host of Canadian goods. Trade negotiations between the United States and Canada collapsed on Friday night, shortly before midnight, the deadline for 50% tariffs to take effect on $20 billion worth of Canadian goods. U.S. Customs and Border Protection issued a bulletin to businesses on Friday warning that its officials would ensure importers complied with the new tariffs starting immediately after the deadline passed. Carney said Friday night that “Canada will match those tariffs dollar for dollar to protect our workers and businesses.” In a statement shared on social media, Carney said important progress had been made in recent weeks to “improve Canada’s position as a country that has the best deal in the world with the United States.” However, that progress fell short of Canada’s goals, he said, adding: “As a result, this afternoon, I have decided to suspend trade negotiations with the United States and have ordered negotiators to return to Ottawa.” The prime minister blamed the United States for the failure of the negotiations. “The last-minute changes to the terms proposed by the United States were unfair, uneconomic and called into question the reliability of any agreement,” Carney said, concluding: “Canada has what the world wants. And we will not allow any nation to determine our future.” In a new social media post Saturday morning, Carney wrote that his negotiators had been working “in good faith” for more than a year, and that in the coming days his government would “release the details of these new tariff measures, which go into effect on the Tuesday after Labor Day.” The United States, in turn, pointed the finger at Canada. Shortly after midnight, U.S. Trade Representative Jamieson Greer responded to Carney with a statement posted on social media saying Canada “had refused to finalize the trade deal under the terms agreed upon earlier this week.” “Despite the United States’ offer to Canada to receive the best deal of any major exporter to our market, new demands and rollbacks of other commitments by Canada have upset the careful balance reached in recent days,” Greer said. He added that earlier this week “the United States agreed to provide an even better deal to Canada, offering significant tariff reductions on steel, aluminum, automobiles and lumber.” “The offer would have led to supply chain coordination in the aerospace sector, complementary actions to address unfair trade practices, cooperation on critical minerals, increased enforcement against imports produced with forced labor, and the announcement of formal negotiations of the United States-Mexico-Canada Agreement (USMCA),” Greer said in his statement. This is a developing story that may be updated.