Elon Musk’s X and xAI filed a lawsuit against Apple and OpenAI on Monday, alleging that the two companies are colluding to stifle competition.

“In a desperate bid to protect its smartphone monopoly, Apple has joined forces with the company that most benefits from inhibiting competition and innovation in AI: OpenAI, a monopolist in the market for generative AI chatbots,” the lawsuit reads, referring to Apple’s partnership with OpenAI to integrate ChatGPT into its systems.

This lawsuit is part of a long series of disputes between Musk and Altman, who continue to throw public jabs at one another. Once a co-founder and co-chair of OpenAI, Musk has sued to block OpenAI’s transition into a for-profit company. He also submitted an unsolicited bid to take over OpenAI for $97.4 billion, which the company rejected.

Musk posted anticompetitive allegations against OpenAI and Apple on X earlier this month, claiming that it’s “impossible for any AI company besides OpenAI to reach #1 in the App Store.”

The partnership between Apple and OpenAI was announced last June, with collaborative features expected to ship in December.

OpenAI and Apple did not immediately respond to a request for comment.