Elon Musk on Monday targeted Apple and OpenAI in an antitrust lawsuit alleging that the iPhone maker and the ChatGPT maker are teaming up to thwart competition in artificial intelligence.

Billionaire entrepreneur Elon Musk’s artificial intelligence startup xAI sued Apple (AAPL) and ChatGPT maker OpenAI in U.S. federal court in Texas on Monday, accusing them of illegally conspiring to thwart competition for artificial intelligence.

Elon Musks firm had previously accused the Cupertino-based tech giant of giving special favor to ChatGPT in its App Store listings and editorial features.