Trade tensions between the United States and Canada are escalating, with President Donald Trump threatening additional 50% tariffs on Canadian vehicles, auto parts and steel as political rhetoric between the longtime allies grows increasingly heated.

Ontario Premier Doug Ford responded sharply to the escalating dispute, twice saying Trump could “kiss my a–” as Canada prepares further measures to protect its economy.

On Monday, Trump announced that tariffs on Canadian cars, trucks, automotive parts and steel would rise to 50% in January. The threat follows a separate round of 50% tariffs on a range of Canadian products that took effect Saturday after negotiations for a broader trade agreement collapsed.

In a social media post, Trump accused Canada of taking advantage of the United States economically for years.

“Tariffs on all Cars, Trucks, both large and small, Automotive Parts, and Steel, will be increased to 50%,” Trump wrote.

Trump also described Canada as one of the most difficult countries for the United States to deal with on trade, claiming that Washington does not need its northern neighbor.

The two economies, however, remain deeply interconnected, with Canada supplying the United States with significant quantities of oil, natural gas and other commodities, while cross-border supply chains are particularly important to the automotive and manufacturing industries.

Canada is now preparing additional measures in response. The Canadian Finance Ministry said several government officials would visit a local business Tuesday before announcing new steps aimed at protecting Canadian workers and companies.

Canadian media reported that the measures are expected to include retaliatory tariffs on U.S. products.

Prime Minister Mark Carney suspended trade negotiations with Washington on Friday after the two sides failed to reach an agreement.

Carney accused the Trump administration of making last-minute changes to the proposed deal that Canada considered unacceptable.

“Last-minute changes in the U.S. proposed terms were unfair, uneconomic, and called into question the reliability of any deal,” Carney said.

He has pledged that Canada will respond “dollar for dollar” to U.S. tariffs, setting the stage for a potentially broader trade confrontation between the neighboring countries.