Economists had already downgraded growth for the European Union, and the new duties would hit industries there especially hard. Companies are looking for ways to blunt the impact.

The European economy, already weakened by an intensifying trade war, faces a new threat after President Trump said on Saturday that he would impose a 30 percent tariff on goods from the European Union. Economists say the move could worsen the region’s struggles in the months ahead.

European Union officials, meeting in Brussels on Sunday, decided to hold off on imposing any countermeasures and continue negotiations in hopes of reaching an agreement before the newly announced measures take effect on Aug. 1.

“At the same time, we will continue to prepare further countermeasures so we are fully prepared,” Ursula von der Leyen, the president of the European Commission, told reporters in Brussels. “We have always been clear that we prefer a negotiated solution.”

E.U. economists recently