Greg Brockman, president of OpenAI, resigned on Friday from OpenAI, hours after the company forced out CEO and cofounder Sam Altman.

“We’ve been through tough and great times together, accomplishing so much despite all the reasons it should have been impossible,” Brockman wrote in a post on X. “But based on today’s news, I quit.”

Earlier in the day, OpenAI ousted Altman from the company after an internal review found he had not been “consistently candid” with his representations to the board. As part of the announcement, the company appointed chief technology officer Mira Murati as interim CEO and demoted Brockman from his role as chairman of the board.

OpenAI didn’t immediately respond to a request for comment.

Altman’s dismissal sent shockwaves through the tech industry, reportedly even blindsiding Microsoft, OpenAI’s most important partner in big tech.

“I loved my time at OpenAI,” Altman posted on X after the announcement. “It was transformative for me personally, and hopefully the world a little bit. Most of all I loved working with such talented people. Will have more to say about what’s next later.”

OpenAI has emerged as one of the most powerful companies in artificial intelligence, in a new era in the mainstream for AI last November, when OpenAI released the wildly popular ChatGPT. The move pushed generative AI to the forefront of Silicon Valley, causing incumbents like Alphabet to beef up their own AI product development.

The sudden reshuffling raises questions about OpenAI’s future without two of its most well-known figures. “Genuinely wishing you all nothing but the best,” Brockman wrote. “I continue to believe in the mission of creating safe AGI that benefits all of humanity.”