Officials in China, Mexico and Canada criticized Tuesday a pledge made by President-elect Donald Trump on social media to impose new tariffs on all three of the United States' largest trading partners on the first day of his presidency.

Trump said the move, which appears to violate the terms of a free-trade deal Trump signed into law in 2020, is aimed at clamping down on drugs − fentanyl especially − and migrants crossing into the U.S. illegally.

The president-elect said he would sign an executive order immediately after his inauguration introducing a 25% tariff on all goods coming from Mexico and Canada and a 10% tariff on goods from China.

Trump takes office on Jan. 20.

"Both Mexico and Canada have the absolute right and power to easily solve this long simmering problem," Trump said in a post on Truth Social, a platform he owns. "It is time for them to pay a very big price!" He accused China in a separate post of failing to block smuggling of U.S.-bound fentanyl, a synthetic opioid.

There was quick pushback to Trump's comments from all three countries.

Liu Pengyu, a spokesperson for the Chinese embassy in Washington, said: "No one will win a trade war or a tariff war" and "the idea of China knowingly allowing fentanyl precursors to flow into the United States runs completely counter to facts and reality."

Mexico's finance ministry said in a statement the U.S.-Mexico-Canada Agreement, a trade pact Trump sponsored during his first term, provided "certainty" for investors. "The response to one tariff will be another, until we put at risk companies that we share," Mexico's President Claudia Sheinbaum said, naming General Motors and Ford, among others. Sheinbaum said her comments, read aloud in a press conference, were sent in a letter to Trump.

Mexico's president: Trump's tariffs will worsen U.S. inflation, kill jobs

Doug Ford, the premier of Ontario, Canada's most populous province, said the tariffs would be "devastating to workers and jobs" in both the U.S. and Canada.

A tariff is effectively a tax imposed by one country on the goods and services imported from another country. Oil is the top U.S. import from Canada, according to the U.S. Energy Information Administration. The largest category of goods imported to the U.S. from Mexico is cars and components for cars. The U.S. imports a significant amount of electronics from China. Some goods are exempt from tariffs because of the U.S.-Mexico-Canada Agreement.

Trump used trade threats as a negotiating tactic during his first term. He slapped tariffs on billions of dollars of Chinese-made goods. Trump had hoped to secure a new trade deal with China, but those plans fell apart with the arrival of the coronavirus pandemic in 2020.

It's unclear whether Trump will follow through on his new tariffs pledge.

Imposing tariffs on U.S. trading partners was a central theme of Trump's economic agenda outlined during his presidential campaign. He appears to believe they will protect U.S. jobs, raise tax revenue and lead to a domestic "manufacturing renaissance." Many economists warn that tariffs drive up inflation and lead to higher interest rates.

Tariffs are paid by importers, not by the countries from where the goods are shipped. Importers typically pass those costs along to consumers by raising the price of each product, making them more expensive.

"Trump got elected to lower the price of groceries. This and deportations will send grocery prices through the roof," said Bill Penzey, the owner of retailer Penzeys Spices, in emailed comments sent before Trump's announcement.

Trump has said once in office he will declare a national emergency and use the military to deport illegal migrants.

"You can’t replace China Garlic with California Garlic when all the people who do the work and have the knowledge in the California Garlic industry have been deported," said Penzey, a frequent Trump critic.

Andrew Law, the founder of The Mexico Brief, a news and analysis platform, said he believes that Trump's announcement is less about tariffs and more about politics.

"The announcement comes right after a diplomatic squabble broke out between Mexico and Canada over Chinese imports. In response, Mexico hastily introduced a law to replace certain Chinese-made parts with Mexican-made ones. Trump sees an opening to push China further out of America’s backyard," Law wrote in a commentary Tuesday.

"This is less a policy declaration than a move to stir up more trouble among bickering allies. The goal? To extract even more concessions from Mexico and Canada on China. He’s throwing a cat among the pigeons to watch what happens. It’ll probably work."

Contributing: Michael Collins, Laura Villagran

(This was updated to include video.)