Tesla CEO Elon Musk on Friday slammed Apple for the fees it charges companies to use its app store – a fee that he likened to a "global tax on the Internet."

"Apple app store fees are a de factor global tax on the Internet," the billionaire tweeted. "Epic is right."

The "Epic" refers to Epic Games Inc., the video game company behind popular titles like "Fortnite" which brought a lawsuit against Apple, charging that the tech giant has transformed a once-tiny digital storefront into an illegal monopoly that squeezes mobile apps for a significant slice of their earnings.

Apple takes a commission of 15% to 30% on purchases made within apps, including everything from digital items in games to subscriptions.

The company has denied Epic’s claims.

FOX Business has reached to Apple for comment on Musk’s comments.