President Trump escalated his fight with Canada on Tuesday, threatening to double tariffs on steel and aluminum imports and pressing to turn one of America’s closest traditional allies into the 51st state. After several tense hours, both sides backed down, at least for now.

It was the latest in a week of chaotic trade moves, in which the president startled investors and businesses that depend on trade and clashed with some of the country’s closest trading partners.

In a post on his social media platform Tuesday morning, Mr. Trump wrote that Canadian steel and aluminum would face a 50 percent tariff, double what he plans to charge on metals from other countries beginning Wednesday. He said the levies were in response to an additional charge that Ontario had placed on electricity coming into the United States, which was in turn a response to tariffs Mr. Trump imposed on Canada last week.

By Tuesday afternoon, leaders had begun to relent. The premier of Ontario, Canada’s most populous province, said he would suspend the electricity surcharge, and Mr. Trump said at the White House he would “probably” reduce the tariff on Canadian metals.

Kush Desai, a White House spokesman, said Tuesday afternoon that Mr. Trump’s threats had succeeded in getting Canada to back down. “President Trump has once again used the leverage of the American economy, which is the best and biggest in the world, to deliver a win for the American people,” he said.

As a result, he said that Canada would face the same 25 percent tariff on metals as all of America’s trading partners will when they go into effect at midnight.

Thank you for your patience while we verify access. If you are in Reader mode please exit and log into your Times account, or subscribe for all of The Times.

Thank you for your patience while we verify access.

Already a subscriber? Log in.

Want all of The Times? Subscribe.