President Donald Trump said Friday he would not give Apple a waiver for Mac Pro computer parts made in China.

“Apple will not be given Tariff waivers, or relief, for Mac Pro parts that are made in China,” he wrote on Twitter. “Make them in the USA, no Tariffs!”

Apple had requested the Office of U.S. Trade Representative to exempt their company from a proposed 25 percent tariff on computer parts from China.

Trump’s announcement on Twitter sent Apple stocks downward on Friday morning.

Apple stock takes a hit immediately after Trump’s tweet https://t.co/Y6vAsOrntQ pic.twitter.com/XTPpHkQnRY — Charlie Spiering (@charliespiering) July 26, 2019

The Wall Street Journal reported in June Apple had decided to move production of the Mac Pro to China, despite threats of economic tariffs in the ongoing trade battle with the United States.

Despite criticism, Apple CEO Tim Cook continues to court Trump, participating in White House events having to do with economic development and tech education. Cook also serves as an adviser on the Trump administration’s workforce development initiative.

Trump happily discusses his relationship with Cook, which includes phone calls and meetings on tech issues. Trump told reporters in June that he met with Cook privately but he did not say what they discussed.