President Donald Trump today said he is considering imposing tariffs on Apple iPhones and laptop computers imported from China, a remark that drove the company’s stock lower in after hours trading.

Trump raised the possibility in an interview today The Wall Street Journal, where he discussed trade policy and his coming meeting with Chinese leader Xi Jinping at a multilateral summit in Buenos Aires.

The president said he’d likely move ahead with boosting tariff levels on $200 billion worth of Chinese goods. Then, he dropped the bombshell about imposing a tariff on Apple devices that are assembled in China, which currently are exempt.

“Maybe. Maybe. Depends on what the rate is,” the president said to The Wall Street Journal about the possible iPhone and laptop tariffs. “I mean, I can make it 10%, and people could stand that very easily.”

This would hardly be welcome news to Apple investors, who’ve been spooked about signs of weaker demand — particularly for the newly introduced iPhone XR and XS Max. Wedbush technology analyst Dan Ives said this left-field remark by Trump will likely add to the “white knuckle period” for investors.

“While we ultimately believe this is all part of a broader negotiation with China as talks heat up over the next week,” Ives wrote. “Now (Apple CEO Tim) Cook and Apple find themselves squarely at the center of the tariff talks which were previously background noise as investors try to gauge what a potential 10% tariff on iPhones and other products would do to demand and unit growth over the next 6 to 12 months if ultimately imposed.”

Trump has taken the position that companies can avoid this pain by simply moving their factories to the U.S. Indeed, Apple talked earlier this year about creating 20,000 new jobs in the U.S. over the next five years, thanks to Trump’s new tax law.

It seems unlikely that Apple would shift its core production to the U.S. in the foreseeable future, Ives notes.

“While we are taking a wait and see approach around if this talk is more bark than bite from the Trump administration, we could see a negative knee-jerk reaction to this latest tariff news in Apple shares that will add to the agita currently around the name,” Ives wrote.

Apple stock is down nearly 2% to $171.51 in after-hours trading.