Microsoft CEO Satya Nadella on Monday announced the hiring of OpenAI's Sam Altman and other members of his team, days after the co-founder of the venture behind ChatGPT was fired.

"The mission continues," Altman, who rose to fame with the launch of the artificial intelligence chatbot last year, posted on X, formerly Twitter.

Nadella wrote on X that Altman "will be joining Microsoft to lead a new advanced AI research team," along with OpenAI co-founder Greg Brockman and their colleagues.

OpenAI's board sacked Altman on Friday, prompting other high-profile departures from the company as well as a reported push by major investors to bring him back.