"If that is not the case, a tariff of at least 25% must be paid by Apple to the US."Adding uncertainty to his ultimatum, Trump later said the tariff wouldn't apply to just the iPhone but also to any smartphone made outside the US.

"I expect iPhones that will be sold in the United States of America will be manufactured and built in the U.S."

Trump told reporters later on Friday that the 25% tariff would also apply to Samsung 005930.KS and other smartphone makers.