Elon Musk has accused Apple of unfairly favoring ChatGPT on its App Store and threatened legal action, triggering a fiery exchange with OpenAI CEO Sam Altman on Tuesday.

"Apple is behaving in a manner that makes it impossible for any AI company besides OpenAI to reach #1 in the App Store, which is an unequivocal antitrust violation," Musk said in a post on his social media network X on Monday, without providing evidence to back his claim.

"xAI will take immediate legal action," he said, referring to his own artificial intelligence company.

X users responded by pointing out that China's DeepSeek AI hit the top spot in the App Store early this year, and Perplexity AI recently ranked number one in the App Store in India.

DeepSeek and Perplexity compete with OpenAI and Musk's startup xAI.

OpenAI CEO Sam Altman called the accusation "remarkable" in a response on X on Tuesday, adding that Musk was alleged to "manipulate X to benefit himself and his own companies and harm his competitors and people he doesn't like."

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.

OpenAI and xAI both released new versions of their AI assistants, ChatGPT and Grok, in the past week.

App Store rankings listed ChatGPT as the top free iPhone app on Tuesday, with Grok in fifth place.

Apple did not respond immediately to a request for comment.

Factors going into App Store rankings include user engagement, reviews and the number of downloads.

- AI wars -

OpenAI and Apple announced an alliance in June last year to enhance iPhones and other devices with ChatGPT features.

ChatGPT-5 rolled out free to the nearly 700 million people who use it weekly, OpenAI said in a briefing with journalists last week.

Tech industry rivals Amazon, Google, Meta, Microsoft and xAI have been pouring billions of dollars into artificial intelligence since the blockbuster launch of the first version of ChatGPT in late 2022.

Chinese startup DeepSeek shook up the AI sector early this year with a model that delivers high performance using less costly chips.

OpenAI filed counterclaims against multi-billionaire Musk in April, accusing its former co-founder of waging a "relentless campaign" to damage the organization after it achieved success without him.

OpenAI alleged in legal documents filed at the time in the northern California federal court that Musk became hostile toward the company after abandoning it years before its breakthrough achievements with ChatGPT.

The lawsuit was another round in a bitter feud between the generative AI (genAI) start-up and the world's richest person, who accused OpenAI of betraying its founding mission in a lawsuit last year.

OpenAI alleged in its countersuit that Musk "made it his project to take down OpenAI, and to build a direct competitor that would seize the technological lead -- not for humanity but for Elon Musk."

Musk founded his own genAI startup, xAI, in 2023 to compete with OpenAI and the other major AI players.

Related Links
All about the robots on Earth and beyond!