"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."

Apple Inc. faces escalating pressure from President Donald Trump to do what many analysts insist would be nearly impossible: move production of its iconic iPhone to the US from overseas.