Apple shares fell as much as 3% on Friday after President Trump said the company must pay at least a 25% tariff, unless iPhones sold in the US are manufactured domestically.

"I have long ago informed Tim Cook of Apple that I expect their iPhone's that will be sold in the United States of America will be manufactured and built in the United States, not India, or anyplace else," Trump said in a Truth Social post on Friday morning.

"If that is not the case, a Tariff of at least 25% must be paid by Apple to the U.S."

Speaking during a Q&A session at the White House on Friday afternoon, Trump suggested the tariff policy would apply not only to Apple but also to competitors like Samsung.

“It would be also Samsung and anybody that makes that product. Otherwise, it wouldn’t be fair,” he said. “Again, when they build their plant here, there’s no tariffs. So they’re going to be building plants here.”

Apple has been caught in the crosshairs of President Trump's tariff policy, which seeks to bring manufacturing back to the US and away from places like China.

In its quarterly earnings call earlier this month, the company revealed it expects to face a $900 million headwind as a result of tariffs in the current quarter.

The company is working to diversify its supply chain, with heavy investments in India. CEO Tim Cook said during the company's earnings call in early May that the "majority" of iPhone sold in the US this quarter would be sourced from India.

"I had an understanding with Tim that he wouldn't be doing this," Trump told reporters on Friday afternoon. "He said he's going to India to build plants. I said, 'That's okay to go to India, but you're not going to sell into here without tariffs.'"

Read more: The latest news and updates on Trump's tariffs

Wall Street has warned that making devices in the US would result in much more expensive phones for customers.

"The pressure from Trump Administration on Apple to build iPhone production in the US as we have discussed this would result in an iPhone price point that is a non-starter for Cupertino and translate into iPhone prices of ~$3,500 if it was made in the US which is not realistic as this would take 5-10 years to shift production to the US," Wedbush analyst Dan Ives said in a note Friday.

"We believe the concept of Apple producing iPhones in the US is a fairy tale that is not feasible," he added.

Yahoo Finance reached out to Apple on Friday but has not yet received a response.