Toronto (AP) — Canadian Prime Minister Mark Carney said Thursday that trade negotiations with the United States had turned “nasty” after President Donald Trump derided Canada’s leadership while threatening to expand tariffs.

Carney said Canada remained engaged, describing the talks as a fight to protect Canadian workers and businesses. “This is a tough negotiation,” Carney said in French. “You can say ‘nasty.’ But this is a question of Canadian jobs. It’s a question of the future of Canadian businesses.” Trump criticized Canada during a speech Wednesday in Las Vegas. “Canada’s nasty. They’re nasty,” Trump said. “I love the people, but they’re nasty. Nasty leadership.”

The United States already has tariffs on Canadian steel, aluminum and automobiles. Trump has threatened to impose 50% tariffs on more Canadian goods beginning Aug. 19. These tariffs raise import costs, which companies may pass to consumers. Trump argues the costs will move manufacturing to the U.S., though data shows little evidence. The president’s tariff threats and suggestions that Canada become the 51st U.S. state have angered many Canadians, prompting cancellations of U.S. trips.

U.S. Trade Representative Jamieson Greer said Canada and China are the only two countries to retaliate, citing restrictions on U.S. alcohol sales in some Canadian provinces. The latest comments followed months of escalating tensions, including Carney’s January criticism at the World Economic Forum in Davos, Switzerland, where Trump responded that “Canada lives because of the United States.” Canada is one of the United States’ largest trading partners, and the move threatens to push prices higher amid the high cost of living ahead of the Nov. 3 midterm elections. Carney noted existing U.S. tariffs on aluminum have contributed to a 58% increase in U.S. aluminum prices, a situation he said is not good for American companies.