WASHINGTON—President Trump ordered federal agencies on Thursday to explore how to adjust U.S. tariffs to match those of other countries, a move that threatens international rules in place for decades.

The president said his advisers would devise new tariff levels reflecting countries’ tariffs, taxes, subsidies and other policies affecting trade with the United States.

4.8%. That’s how much the U.S.’ weighted average tariff rate would be if Trump implemented the country-level strategy, Deutsche Bank economists led by Justin Weidner estimated in a Monday note. That’s a 3.3 percentage-point increase from the 1.5% effective rate U.S. imports had in 2022, according to the World Bank.