President Trump said early Friday morning that he is set to resume a set of tariffs that he initially imposed in April on dozens of countries, before pausing them for 90 days to negotiate individual deals.

Most of those deals have yet to materialize, and businesses in the United States have been left guessing what levies they would be expected to pay on virtually every imported product.

Some of them could be even steeper than originally announced, Mr. Trump said in brief remarks to reporters at Andrews Air Force Base upon returning from a rally in Iowa on Thursday.

“So we’re going to start sending letters out to various countries starting tomorrow,” said Mr. Trump, hours after his major domestic policy bill passed the House of Representatives. “They’ll range in value from maybe 60 or 70 percent tariffs to 10 and 20 percent tariffs.”

He said his administration would then send more letters each day until the end of the 90-day pause, on Wednesday, when he expected they would all be covered. Smaller countries would come toward the end, and duties would begin to be collected on Aug. 1.

“It’s a lot of money for the country, but we’re giving them a bargain,” Mr. Trump said.

The original round of “reciprocal” tariffs was imposed on trading partners and ranged from 11 percent, for the Democratic Republic of the Congo, to 50 percent, for Lesotho. The duties were decided using a formula that incorporated the trade balance between each country and the U.S. — even for tiny countries that had very little ability to buy goods from America. The reciprocal tariffs came on top of a 10 percent “baseline” tariff imposed on all countries.