President Trump has replaced an expiring global tariff with new duties on goods from 59 countries and the European Union. The measures took effect at 12:01 a.m. Eastern on Friday.
The new tariffs carry two rates of 10 percent and 12.5 percent. They apply to imports from the United States' 60 largest trading partners and cover more than 99 percent of all U.S. imports.
The administration said the duties address imports made with forced labor. A senior official told reporters the timing was chosen to limit disruption for businesses.
Some categories, including energy and many foods, are exempt. The move follows a Supreme Court ruling that struck down earlier tariffs imposed under the International Emergency Economic Powers Act.
Critics, including Senator Ron Wyden, accused the administration of using forced-labor claims to revive policies the court had rejected.