Trump threatened to impose the costly tariffs on the European Union starting on June 1, complaining last week that the negotiations were “going nowhere.” He ended up delaying the tariffs on Sunday after speaking with the president of the European Commission.

The twin threats, delivered via social media, roiled global markets after weeks of de-escalation had provided some reprieve.

Stock markets declined after the president’s early-morning threats of 25 percent import taxes on iPhones and 50 percent on goods from Europe.