Elon Musk's artificial intelligence company, xAI, says an “unauthorized modification” led its Grok chatbot to post unsolicited claims on social media about the persecution and “genocide” of white people in South Africa.

The announcement was made at Microsoft’s Build developer conference on Monday, and was notable given Microsoft’s partnership with OpenAI. Musk founded xAI, the startup behind Grok, but he has also been locked in a feud with OpenAI since stepping down from its board in the late 2010s, citing disagreements over its leadership direction.