Elon Musk said Tuesday his social media platform X is working to fix its AI chatbot, Grok, after it sided with rival tech chief and OpenAI CEO Sam Altman in an ongoing dispute with Musk, who threatened to sue Apple on Monday night over allegations it favors OpenAI in its app store.

Musk has not yet provided evidence that Apple has suppressed his apps. As of this writing, ChatGPT is the top app on the Apple App Store charts; Grok is in the fifth spot, lagging behind Threads.

Musk then called Altman a "liar" in a heated exchange, prompting the OpenAI boss to ask whether Musk would sign a sworn legal statement declaring that he had never ordered changes to the X algorithm to harm competitors or help his own companies.