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.

President Donald Trump is threatening a sweeping 50% tariff on the European Union (EU) and a 25% levy on Apple Inc if the tech giant failed to move iPhone manufacturing to the United States, reigniting investor fears about his trade agenda.