AI agents unleashed by OpenAI used more than 10 previously undisclosed websites for unsanctioned communications earlier this year, according to six sets of independent investigators and data reviewed by Reuters, showing that the agents’ rogue activity was wider ranging than previously disclosed.

Although the behavior falls short of hacking and is in some ways closer to spam, the revelation that OpenAI’s agents circumvented their own restrictions to open communications channels on so many different sites — and that the company kept it quiet for months — may drive concerns both over the increasing capacity of AI models and the secrecy of the companies developing them.

The scope of the agents’ unauthorized communications was “somewhat larger than we thought it was,” said Andrew Yoon, a researcher with the California nonprofit CivAI who said he tallied 18 previously undisclosed sites used by the agents between May and July. “It’s almost certain that there’s more going on here that we just don’t know about.”

On Friday, researchers reported that a swarm of agents from OpenAI hijacked a German-language wiki site and turned it into an improvised messaging platform for cheating on tests, an incident that OpenAI kept secret as it dealt with the fallout from the July hack of the open-source repository Hugging Face.

Now, both those researchers and other independent investigators say they have found several previously undisclosed sites where the same swarm appears to have left similar messages earlier this year.

OpenAI did not directly address questions about how many different sites its agents used to communicate or say why it kept the activity under wraps for months. In a statement, it said it was undertaking a broader review of agent activity and had so far “not identified other activity matching the severity or scale of Hugging Face,” a breach that drew global attention and raised concerns that OpenAI was losing control of its own technology.

Read More: OpenAI’s rogue agents used at least 10 more sites for unauthorized comms