The 15% tariff would be lower than previously threatened, but it would remain a high duty on America’s largest trading partner.

The European Union and the United States reached a new trade agreement on tariffs over the weekend, which is expected to result in only modest increases in the cost of cars and auto parts imported from EU countries,

But as recently as Wednesday, Mr. Trump floated a higher range, between 15% and 50%. Mr. Trump, who in April said the U.S. had 200 trade deals with other nations, has since said there are too many countries for individual trade deals with all of them and the U.S. will have "simple" tariffs for "most" countries.

Trump had most recently threatened tariffs of 30% on imports from the European Union. But on Sunday, he met with the president of the European Commission, and they agreed to a lower level.