OpenAI Interim Chief Executive Officer Mira Murati was “honored and humbled” to step into the leadership role at the company following the ouster of Sam Altman, according to a memo she sent to staff reviewed by Bloomberg.

Murati also urged employees still reeling Friday from the sudden departure of Altman, one of the most prominent figures in the artificial intelligence industry, to focus on their work. “It’s more important than ever that we stay focused, driven, and true to our core values,” she wrote.

In the immediate aftermath of the announcement, speculation was rife that Microsoft Corp., the world’s largest maker of software and OpenAI’s biggest backer, might have been involved in his removal. However, Redmond, Washington-based Microsoft didn’t orchestrate Altman’s exit, according to two people with knowledge of the matter who asked not to be identified because the information isn’t public.

The software giant had only a few minutes advanced notice about Altman’s firing, said a person familiar with the matter.

Microsoft Chief Executive Officer Satya Nadella tried to ease any concerns Altman’s departure could hurt his company’s long-term AI plans. Microsoft Friday ended a three-day conference in which it unveiled a new AI chip that OpenAI said it is testing, as well as various new programs and updates, many of them based on the startup’s technology.

“We have a long-term agreement with OpenAI with full access to everything we need to deliver on our innovation agenda and an exciting product roadmap; and remain committed to our partnership, and to Mira and the team,” Nadella wrote in a blog post. “Together, we will continue to deliver the meaningful benefits of this technology to the world.”

Murati said that she had spoken to Microsoft’s leadership on Friday. “I spoke with Kevin and Satya earlier today who expressed their unwavering support,” she wrote in the memo, referring to Microsoft Chief Technology Officer Kevin Scott and Nadella.

OpenAI is at a“crucial juncture where our tools are being widely adopted, developers are actively building on our platforms, and policymakers are deliberating on the best ways to regulate these systems,” Murati wrote. “This is welcome progress and an opportunity to participate in a future where AI is built and used for good.”

Murati did not mention Altman by name in the memo.

(Updates with context on Microsoft starting in the third paragraph.)