In his essay, called We Must Pace the Frontier and made public on Saturday, Amodei proposed a three-point plan that includes independent monitoring of AI models as they are developed, industry-wide regulation and global regulation.

As his proposal made the rounds, even competitors voiced support for the idea of third-party monitors who could evaluate the safety of models as they are developed.

"I agree with Dario that we need to pace the frontier," wrote OpenAI CEO Sam Altman on X. He called independent evaluators "a great idea."

In a new interview with Fortune Magazine, Altman had sounded similar safety concerns, saying standards were "not at a place" to push AI capabilities much further.

He added that he believed AI beyond human control is "absolutely" possible.

Elon Musk meanwhile said the Anthropic boss was "right".

The warnings have prompted calls to action, but US President Donald Trump has so far rejected such fears, saying on Thursday he was concerned "if we don't win AI, we're going to be put in a very bad position".

Some observers have also suggested that Amodei's post may be less about safety than about consolidating control over AI technology.

Cyber-security concerns have grown as new models have exhibited more and more powerful hacking capabilities.

Anthropic withheld its Mythos model from public use when it was announced in April that it could independently escape the testing environment, known as the sandbox.

In the run-up to the release of its most recent Astra model, OpenAI cited cybersecurity concerns as it explained it had paused certain aspects of the model's development.

Safety has also taken centrestage in the rivalry between Anthropic and OpenAI.

Amodei, who had previously worked as a vice president at OpenAI, has said he co-founded Anthropic in 2021 so he could build safer and more trusted AI models.

In his essay, Amodei pointed out that AI had advanced "drastically faster" including its "ability to build the next generation of AI" - and mentioned an incident involving rival OpenAI which has revealed that agents conducted cybersecurity attacks, external on targets they were not asked to attack in July.

The OpenAI agents had "essentially acted as a fanatically devoted collective", Amodei said. OpenAI has said it is slowing down training of certain advanced AI models and tools as a result.

Amodei called for "building AI at a balanced rate that aims to ensure its safety while still achieving its benefits".

This would not mean "halting model training or technical progress, but ensuring companies take adequate time to align and safeguard their models, and for third party evaluators to confirm this".

He was committing Anthropic to this "unilaterally" - as well as calling on governments "to require other frontier companies to match".

Amodei said he recognised that regulation might not be able to keep up with the pace of AI, and therefore called on AI companies to "voluntarily work together to set standard" in parallel with regulation.

The Anthropic CEO went on to address the impact that a slowdown would have on the industry and competition with leading developers worldwide, particularly China.

"I believe that if slowing down bought us even an extra year or two before models reach critical levels of capability, and we used that time to advance alignment, we could greatly reduce the risk that something goes seriously wrong," Amodei said.

This would have to be done in a co-ordinated manner "without sacrificing commercial advantage or the United States' lead in AI". Any slowdown would have to be limited, he said, to avoid allowing China to pull ahead.

He urged the US government to take measures so that US companies' AI chips could not be sold to China - or the technology shared with authoritarian countries.

His former employee, Jacob Coxon, told the BBC, however, that the initiative to slow down must go beyond the US - "there'll need to be some sort of co-ordinated slowdown with China if we're going to avoid a race at an international scale".

Amodei's post has prompted a wide range of responses.

Clement Delangue, the CEO of the AI platform Hugging Face, said he was launching a new project called the Open Alignment Initiative, adding he wanted to be among "embedded evaluators" that Amodei proposed could be part of a solution.

Hugging Face was hacked by OpenAI agents earlier this year prompting an outcry over AI safety.

"Let's make AI safer by making it more transparent." Delangue wrote on X.

Elon Musk also voiced his support, writing that "Dario is right".

Musk, whose SpaceXAI makes the controversial chatbot Grok, once called Anthropic "evil" but has changed his tone since signing a $15bn deal to sell compute capacity to Anthropic in May.

However some observers suggested that Amodei's post was less about safety than about consolidating control over AI technology.

"Dario makes the case to stop open source and concentrate enormous technological and economic power with Anthropic," wrote Chamath Palihapitiya, investor and co-host of the tech podcast "All-In".

Notions of slowing down or even pausing AI development have long been met with such cynicism in certain corners of Silicon Valley, with critics accusing leading AI developers of hyping their technology as a marketing ploy.

Anthropic and OpenAI are both reportedly preparing for potentially record-setting initial public offerings.