“I’m sure you all are feeling confusion, sadness, and perhaps some fear,” Brad Lightcap, OpenAI’s chief operating officer, said in a memo to OpenAI employees. “We are fully focused on handling this, pushing toward resolution and clarity, and getting back to work.”

On Friday, Mr. Altman was asked to join a board meeting via video at noon in San Francisco. There, Mr. Sutskever, 37, read from a script that closely resembled the blog post the company published minutes later, according to a person familiar with the matter. The post said that Mr. Altman “was not consistently candid in his communications with the board, hindering its ability to exercise its responsibilities.”

But in the hours that followed, OpenAI employees and others focused not only on what Mr. Altman may have done, but on the way the San Francisco start-up is structured and the extreme views on the dangers of A.I. embedded in the company’s work since it was created in 2015.

Mr. Sutskever and Mr. Altman could not be reached for comment on Saturday.

In recent weeks, Jakub Pachocki, who helped oversee GPT-4, the technology at the heart of ChatGPT, was promoted to director of research at the company. After previously occupying a position below Mr. Sutskever, he was elevated to a position alongside Mr. Sutskever, according to two people familiar with the matter.

Mr. Pachocki quit the company late on Friday, the people said, soon after Mr. Brockman. Earlier in the day, OpenAI said Mr. Brockman had been removed as chairman of the board and would report to the new interim chief executive, Mira Murati. Other allies of Mr. Altman — including two senior researchers, Szymon Sidor and Aleksander Madry — have also left the company.