President Trump said on Tuesday that he intended to impose a 10 percent tariff on Chinese imports into the United States on Feb. 1, a decision that is sure to escalate trade tensions between the world’s largest economies.

Speaking at the White House, Mr. Trump said that the tariffs were in response to China’s role in America’s fentanyl crisis. Mr. Trump said that China was sending fentanyl to Canada and Mexico, from where it would be transported into the United States.

The tariff threat comes after Mr. Trump said on Monday that he planned to impose a 25 percent duty on imports from Canada and Mexico as punishment for allowing fentanyl and illegal immigrants to cross into the United States.

“We’re talking about a tariff of 10 percent on China based on the fact that they’re sending fentanyl to Mexico and Canada,” Mr. Trump said.

At a news briefing in Beijing on Wednesday, Mao Ning, a spokeswoman for China’s Foreign Ministry, said China would “safeguard” its interests. “We always believe there is no winner in a tariff or trade war,” she added.

Those tariffs would come on top of levies that Mr. Trump imposed on more than $300 billion worth of Chinese imports during his first term. Those tariffs were kept in place by former President Joseph R. Biden Jr., who imposed additional levies on Chinese electric vehicles, solar cells, semiconductors and advanced batteries.