Several of Anthropic’s state-of-the-art artificial intelligence models recently broke into the systems of three outside organizations, the start-up said on Thursday, a surprise revelation nine days after a similar incident at the rival start-up OpenAI.

The breaches, which date as far back as April, were discovered when Anthropic carried out a review of its systems. Anthropic, which did not disclose the identities of the three organizations, said it had informed them this week about the incidents.

The review was spurred by OpenAI’s disclosure that it had hacked into a popular A.I. library, Hugging Face, while testing the cybersecurity abilities of its systems.

The incidents have rattled security specialists and computer scientists. For years, A.I. researchers warned that because the technology was advancing so rapidly, it could soon spiral out of human control without proper safeguards around the tech.

Employees at Anthropic and OpenAI warned that these programs were already beginning to display the worrying types of science-fiction scenarios that the industry had long warned would become a reality.

“With tighter monitoring and controls around evaluation infrastructure, as well as continued investment in alignment, this type of risk can be overcome,” Anthropic said in a blog post detailing the incident.

This is a developing story. Check back for updates.