It comes just days after rival OpenAI said rogue AI agents had breached other firms' networks.

US technology firm Anthropic says its AI models hacked into the systems of three organisations on their own, during a private security experiment. The models found a weakness in what was supposed to be an isolated test environment and connected to the internet. It comes just days after rival OpenAI said that its models had breached the systems of other companies, including AI tools hub Hugging Face. The announcement prompted Anthropic to check whether its own systems had carried out similar attacks. It says it uncovered three cases which have since been reported to the affected companies. Anthropic, which did not name the organisations, urged other AI labs to perform similar reviews to better understand the risks of their models' capabilities. Anthropic said in a statement, external it reviewed more than 140,000 tests to find evidence Claude - its family of AI models - had managed to get online even though it was supposed to be in an isolated test environment, cut off from the internet. The tests included exercises in which Claude was tasked with obtaining "secret" information hidden on another machine on the closed-off network. It was then told to get the information by breaking into the machine and finding it - a common way that experts assess a model's hacking capabilities.