A spokeswoman added that the same person had "also made threats at our San Francisco headquarters".

"Thankfully, no one was hurt," the spokeswoman said. "We deeply appreciate how quickly SFPD responded and the support from the city in helping keep our employees safe."

Although the man had fled the scene outside Altman's home by the time police arrived, about an hour later he showed up outside an OpenAI office and threatened to "burn down the building", police said. He was then arrested.

An officer for the SFPD declined to comment on whether the man was still under arrest as of Friday afternoon or if and when he would be charged with a crime, saying it was "an active and open investigation".

Altman is a billionaire and the owner of a number of properties, but his main residence is in San Francisco, where OpenAI was founded and operates.

A leading figure in the world of AI, Altman has become one of the most famous tech executives in the world.

His firm's release of the chatbot ChatGPT in late 2022 gave rise to the technology industry's current pursuit of advancements in and new tools driven by AI. It has driven hundreds of billions of dollars a year in financial investment.

While the broader impacts of AI are still unclear, OpenAI claims the technology will cause major social and economic upheaval, driven by significant displacement of workers as AI capabilities become more sophisticated and applicable to nearly all forms of work.

Earlier this week, the company put forward several ideas for government policies that could stem any ill-effects of AI and kept "people first", including job training, upskilling for AI tools and increased taxes on corporations.