US President Donald Trump on Friday threatened Apple with a 25 percent tariff if iPhones were not built in the United States, sending the company’s share price sharply lower.

Apple has become a main target of Trump’s anger at companies keeping their manufacturing overseas and his singling out of a specific company for tariffs is highly unusual.

While designed in the United States, most of Apple’s iPhone assembly happens in China, which is caught up in a bitter trade war with the US.

As a workaround, Apple has made announcements that it was shifting production to other countries, including India, but the US president said this would not solve the problem.

In a post on Truth Social, Trump said he had “long ago informed Tim Cook of Apple that I expect their iPhones that will be sold in the United States of America will be manufactured and built in the United States, not India, or anyplace else.”

“If that is not the case, a Tariff of at least 25 percent must be paid by Apple to the U.S.,” he added.

Trump’s comments Friday echoed statements he made last week while on a trip to Qatar, urging Apple to bring iPhone production to US shores.

“I had a little problem with Tim Cook,” Trump said on May 15.

The president said he told Apple chief executive Cook: “We’re not interested in you building in India… we want you to build here and they’re going to be upping their production in the United States.”

Analysts broadly agree that shifting iPhone manufacturing to the United States is unrealistic, and would require a major rethink of the company’s business model that could take many years, if possible at all.

Despite some shift in production, about 90 percent of Apple’s iPhone production and assembly is based in China, according to Wedbush Securities’ estimates.

Reshoring iPhone production to the United States “is a fairy tale that is not feasible,” Wedbush Securities analyst Dan Ives said in a note.

With constant pressure coming from the White House, Apple’s share price has shed more than 20 percent since the beginning of the year when Trump took office with his protectionist agenda.

On Friday its shares were trading a little below three percent.

In the first Trump term, Apple was given exceptions to the White House’s onslaught on China trade ties, but this time around his company has become a regular presidential target.

Cook last month warned of the uncertain impact of US tariffs on products from China, which at one point stood at 145 percent, despite a temporary reprieve for high-end tech goods such as smartphones and computers.

He said that Apple expects US tariffs to cost $900 million in the current quarter.

“Prices of handsets look set to rise, given iPhones will end up being more expensive, if the threats turn into concrete trade policy,” said Susannah Streeter, analyst at Hargreaves Lansdown.

“While die-hard fans will still be prepared to pay big bucks for Apple’s kit, it’ll be much harder for the middle-class masses who are already dealing with price hikes on other goods, from Nike trainers to toys sold in Walmart,” she added.

Last week, the US and China slashed the sweeping tariffs on each other’s goods for 90 days, marking a temporary de-escalation in a brutal trade war.