The decision came just hours after OpenAI disclosed Friday that it was reviewing incidents from the summer involving agents that gathered and distributed information from federal government websites in unexpected ways.

Separately, AI evaluator Transluce said agents that appeared to come from OpenAI unsuccessfully attempted to hack into a US Department of Education website, although OpenAI has not confirmed the claim.

OpenAI said it will resume training “only when we are confident that we have additional safeguards” in place, adding that it expects it will have to “hit pause” again as AI develops and new issues emerge.

Meanwhile, Australia’s prime minister, Anthony Albanese, said last week that an OpenAI agent had breached the government’s national healthcare system, although he said no sensitive information had been compromised.

AI labs are facing pressure from lawmakers and technology experts to slow development so they can build safeguards against agents acting independently, hacking websites and disclosing nonpublic information.

The heads of OpenAI and rival Anthropic have also called for a slowdown.

This is the second time in three months that OpenAI has halted development of its models.

The first pause came in July after the disclosure of a cyberattack targeting AI startup Hugging Face, an incident that raised concerns about the industry’s ability to control increasingly capable AI systems.

At the same time, governments are discussing how to address emerging AI risks.

In a meeting with Chinese President Xi Jinping this week, US President Donald Trump agreed to share information on AI dangers and coordinate efforts to keep the technology safe.

Trump has said he believes fears about AI are overblown and later suggested that he does not plan to impose his own crackdown.

The US is not going to be “putting on brakes”, Trump told reporters outside the White House.

“They want to stop our progress because we’re leading China by a lot, and we’re going to keep it that way.”

The latest OpenAI incidents did not appear to involve the disclosure of nonpublic information, but they were concerning enough for the company to warn the federal agencies involved.

In the Department of Education incident, OpenAI agents found API “developer keys” that could provide access to government data, although the agents ultimately gathered only publicly available information.

In a separate case involving the securities and exchange commission, agents found information freely available to the public and then posted it elsewhere on the internet, going beyond their instructions.

US Securities and Exchange Commission spokesperson Kurt Hopfenspirger said on Saturday that “no nonpublic information was accessed”.

The Department of Education said earlier that it found “no evidence of any impact to our website or databases”.

Several other AI companies have also disclosed incidents involving models that acted unexpectedly or attempted to hack websites.

OpenAI’s CEO, Sam Altman, said in a social media post on Friday that the Hugging Face incident “is still the most severe event we’ve seen”.

OpenAI has previously shared six other reports of “unexpected or concerning” behavior in AI models and introduced a framework for tracking, probing and disclosing such incidents.