May 14 (Reuters) -

OpenAI co-founder and chief scientist Ilya Sutskever is

leaving the startup at the center of today's artificial

intelligence boom.

"OpenAI would not be what it is without him," OpenAI CEO Sam

Altman wrote in a message to the company, which OpenAI posted on

its blog.

Microsoft ( MSFT )-backed OpenAI makes the popular ChatGPT

chatbot, which sparked a race among the world's largest tech

companies for dominance in the emerging generative AI field.

Jakub Pachocki will be the company's new chief scientist,

the company said on its blog.

Pachocki has previously served as OpenAI's director of

research and led the development of GPT-4 and OpenAI Five.

"After almost a decade, I have made the decision to leave

OpenAI," Sutskever said in a post on X.

Sutskever posted that he is working on a new project "that

is very personally meaningful to me about which I will share

details in due time."

Sutskever played a key role in Altman's dramatic firing and

rehiring in November last year. At the time, Sutskever was on

the board of OpenAI and helped to orchestrate Altman's firing.

Days later, he reversed course, signing onto an employee

letter demanding Altman's return and expressing regret for his

"participation in the board's actions."

After Altman returned, Sutskever was removed from the board

and his position at the company became unclear.

Sutskever's exit comes a day after the company said at an

event on Monday that it would release a new AI model called

GPT-4o, capable of realistic voice conversation and able to

interact across texts and images.

Shortly after launching in late 2022, ChatGPT was called the

fastest application ever to reach 100 million monthly active

users. However, worldwide traffic to ChatGPT's website has been

on a roller-coaster ride in the past year and is only now

returning to its May 2023 peak, according to analytics firm

Similarweb.

Sutskever has long been a prominent researcher in the AI

field. Before founding OpenAI, he worked as a researcher at

Google Brain, and was a postdoctoral researcher at

Stanford, according to his personal website. He started his

career working with Geoffrey Hinton, one of the so-called

"godfathers of AI".