San Francisco, California - An artificial intelligence researcher who left OpenAI to join Anthropic has decided to leave the industry, accusing both companies of "gambling with our lives" in the race to develop AI models capable of self-improvement.

Jacob Coxon (27) spent the past three years pretraining AI models, first at OpenAI and then, this year, at its rival Anthropic, which he considered more cautious in its approach.

Pretraining is the stage where AI models absorb vast quantities of data.

"Neither company is acting responsibly. They are racing straight to self-improving superintelligence and gambling with our lives," Coxon said on Tuesday.

"The people building AI earnestly believe that it could kill us all by the end of the decade," he said in a post on X.

"This is not a marketing stunt," he added.

Superintelligence is the theoretical point when AI's capabilities exceed human intelligence.

Anthropic safety executive Evan Hubinger backed up Coxon on X.

"We really do earnestly believe AI could kill all humans!" he said, adding that he estimated that risk at more than 10 percent over the next decade.

Hubinger said Anthropic is "trying its best", but does not yet have a plan to ensure an AI system that surpasses human capabilities would obey its creators. He said there was a "low" risk of that happening with current models.

Coxon's resignation comes as Anthropic prepares for its market debut, following a summer marked by unauthorized hacks carried out by AI tools during testing.

AI leaders say so-called "recursive self-improvement," a stage where AI systems could essentially design and train the next generation of AI with little human involvement, is drawing near.

Coxon considers Anthropic's efforts genuine but said he believes no company can responsibly develop an AI that surpasses humans without government intervention or a coordinated slowdown.

"At Anthropic, the stakes are well-understood, but they are locked in a race to get there first – they believe no one else will act responsibly, so they must do it themselves, despite the risk," he said.

In February, Anthropic removed a pledge from its safety charter to halt the development of its models if it failed to control their risks.

It argued that if it unilaterally paused its work, its less cautious rivals would dominate the industry, making it less safe overall.

At the end of July, more than 1,000 tech industry employees, including Anthropic's CEO Dario Amodei, called on Washington to support a coordinated slowdown in the development of the most advanced AI systems.

OpenAI halted training of its latest models for two weeks in August before resuming it under tighter controls.

On Sunday, OpenAI's chief scientist, Jakub Pachocki, called for "extreme caution."

"International coordination on future AI development needs to become a top priority for governments around the world," he said in a blog post.

AI models are not regulated by federal law in the US.

In September, Senator Bernie Sanders and Democratic Representative Greg Casar introduced a bill seeking to suspend AI development until a federal regulator is created.