Elon Musk, who owns SpaceX, Tesla, and X, is planning to take legal action against Apple because his apps, X and Grok, aren’t featured as top recommendations in the App Store.

In a post on X late Monday, Musk questioned Apple’s decision not to include X and Grok in its ‘Must Have’ section. He highlighted that X holds the top spot as the leading news app globally, while Grok ranks fifth among all apps, suggesting potential political bias behind Apple’s choices.

Grok is owned by Musk’s artificial intelligence startup xAI.

Musk alleged that Apple is creating barriers that prevent any AI firm other than OpenAI from achieving the number one spot in the App Store, calling it a clear antitrust breach. He stated that his company, xAI, would pursue legal measures promptly.

He gave no further details.

There was no immediate comment from Apple, which has faced various allegations of antitrust violations in recent years.

A federal judge recently found that Apple violated a court injunction in an antitrust case filed by Fortnite maker Epic Games.

The European Union, which consists of 27 countries, penalized Apple 500 million euros in April for violating competition laws by hindering app developers from directing users towards more affordable options outside of its App Store.

The prior year, the EU imposed a nearly $2 billion fine on the American tech company for giving an unfair advantage to its own music service and restricting competitors, such as Spotify, from informing users about cheaper subscriptions available outside iPhone apps.

By early Tuesday, the leading app in Apple’s App Store was TikTok, followed by Tinder, Duolingo, YouTube, and Bumble, with OpenAI’s ChatGPT in 7th place.