U.S. President Donald Trump’s long-threatened trade war with the country’s three largest trading partners has become a reality. The United States imposed 25 percent duties on almost all goods from Canada and Mexico early Tuesday, while hitting China with another round of 10 percent tariffs—on top of the 10 percent announced last month.

Trump’s reasoning: the countries’ alleged failure to stem the flow of fentanyl and immigrants into the United States. Having failed to satisfy Trump’s shifting demands, Canada, Mexico, and China are now hitting back.

In a fiery speech on Tuesday, Canadian Prime Minister Justin Trudeau accused Trump of trying to engineer “a total collapse of the Canadian economy because that will make it easier for him to annex us.” He announced 25 percent retaliatory tariffs on $155 billion worth of U.S. imports; duties on $30 billion of that will start immediately.

South of Washington, Mexican President Claudia Sheinbaum also vowed retaliatory measures, to be announced this coming Sunday. “We don’t want to enter into a trade war,” Sheinbaum said, adding that she hopes her scheduled meeting with Trump on Thursday avoids the need for such a response. Like Trudeau, Sheinbaum emphasized Mexico’s right to sovereignty in the face of U.S. aggression.

China, for its part, announced new 10 to 15 percent tariffs on U.S. agricultural goods—including chicken, corn, pork, and soybeans—to go into effect on March 10. These retaliatory measures apply to a wider range of products than China’s initial tariffs against the United States last month, and they target U.S. farmers who are heavily reliant on the Chinese market.

Taken together, Canada, Mexico, and China account for more than 40 percent of U.S. imports. Stocks tumbled globally on Tuesday morning, with the S&P 500 falling 1 percent after taking its biggest drop of the year yesterday ahead of the tariffs going into effect.