Elon Musk’s legal battle with his artificial intelligence rivals is escalating, as his company xAI filed a lawsuit against Apple and OpenAI, accusing them of collaborating to undermine the development of its chatbot, Grok.

The lawsuit, filed Monday in the U.S. District Court for the Northern District of Texas, claims that Apple is using the App Store to restrict the distribution of Grok, which operates both as a standalone app and as an integrated feature of the social network X. xAI is seeking billions of dollars in damages, arguing that Apple and OpenAI’s partnership maintains monopolistic practices and excludes innovative competitors.

“By acting in coordination, defendants Apple and OpenAI have locked up the markets in order to preserve their monopolies and prevent innovative companies such as X and xAI from competing,” the lawsuit states.

Musk co-founded OpenAI in 2015 but became sharply critical after the company shifted from a nonprofit model to a commercial one, turning ChatGPT into a leading AI product.

Since then, he has repeatedly condemned OpenAI’s direction and has pursued legal action against its corporate structure.

The lawsuit against Apple comes just weeks after it announced a partnership with OpenAI to integrate ChatGPT technology into its software—a move that drew criticism, given Apple’s lack of strong in-house AI solutions.

Apple insists the agreement is not exclusive, and according to Bloomberg, the company is also in talks with Google to bring its AI technology to iPhones.

App store rankings illustrate the gap: on Monday, ChatGPT held the top spot among free apps on both iOS and Android, while Grok ranked 26th on Apple’s App Store and 47th on Google Play.

Neither Apple, OpenAI, nor Musk’s legal representatives have commented on the lawsuit.