OAKLAND, California: Sam Altman took the witness stand Tuesday in the closely watched lawsuit brought by Elon Musk, defending his leadership of OpenAI and the company's transformation into one of the world's most valuable artificial intelligence firms.

Musk, an OpenAI co-founder and early backer, is seeking Altman's removal from the company and accuses him and OpenAI President Greg Brockman of abandoning the organisation's original nonprofit mission.

OpenAI, which created ChatGPT, is now valued at about $852 billion.

In his testimony, Altman said he became concerned about Musk's efforts to gain greater control over the company as OpenAI worked toward developing artificial general intelligence, or AGI.

"Part of the reason we started OpenAI is we didn't think AGI could be under the control of any one person," Altman said, describing what he called a "particularly hair-raising moment when my co-founders asked Mr. Musk about, well, ‘If you have control, what happens when you die?'"

Altman said Musk replied that control might "pass to my children," a response he said made him uncomfortable.

The case has exposed years of internal conflict over OpenAI's governance and rapid shift from a nonprofit research lab into a commercial powerhouse competing with Musk's AI venture and rival Anthropic

."This is not looking good for any of them, and I think that that's a little bit unfortunate for the AI industry at a time when the public perception of AI is quite negative and seems to be getting worse," said Sarah Kreps, director of Cornell University's Tech Policy Institute.

Musk initially sought personal damages but later dropped that claim. He is now asking the court to direct an unspecified amount of money to OpenAI's charitable arm.

In a text exchange with Brockman, Musk warned that he and Altman "will be the most hated men in America" because of the trial.

Jurors have heard testimony from former board members and executives about Altman's brief ouster in 2023 and concerns over his management style.

Former board member Helen Toner testified that the decision to remove Altman was based on "a pattern of behavior" involving "his honesty and candor, his resistance of board oversight."

OpenAI co-founder Ilya Sutskever testified that Altman displayed a "consistent pattern of lying," but later backed his reinstatement to prevent the company from collapsing.

OpenAI began presenting its defence this week. Board Chair Bret Taylor told jurors: "I think Sam has done a great job as CEO. He's been forthright with me and the other board members."

Legal experts said Altman's testimony could play a critical role in determining both the outcome of the case and his future at OpenAI.