The cybercriminal group ShinyHunters has claimed it breached the FBI and stole terabytes of sensitive personal information about nearly all of the agency’s agents and their spouses, as well as people who had applied for jobs there.

ShinyHunters is a prolific hacking and extortion group linked to large-scale data thefts targeting major companies and government organizations. The FBI itself warned about the group in May.

“We have compromised the FBI. We hold very sensitive data on almost ALL FBI Agents and individuals who filed an application with the FBI” for employment, the group announced on its dark-web leak site on Tuesday. It reportedly released a sample of the purportedly stolen data and a screenshot of a defaced FBI recruitment website.

The group claimed to have taken terabytes of information, including names, home addresses and phone numbers. Reuters reported that it was able to find apparent matches for some individuals contained in a sample of the data, but could not establish that the information had actually been taken from FBI systems.

The FBI has not confirmed the breach or the scale of the alleged data theft. However, a spokesperson allegedly told 404 Media that the bureau was “aware of claims regarding unauthorized activity affecting FBIjobs.gov and is currently investigating.” TechCrunch also reported that the agency’s jobs website and special-agent applicant portal were temporarily unavailable.

According to ShinyHunters, the intrusion began with the compromise of an Oracle PeopleSoft server, which runs software commonly used by human resources departments to handle employee and applicant information. The hackers reportedly claimed they were then able to move into an Amazon-hosted government cloud environment containing FBI personnel and applicant data. Neither the FBI nor the companies involved have publicly confirmed that account.

The hackers said the attack was “not financially motivated.” Instead, they are demanding that the FBI remove a cybersecurity advisory published in May that ShinyHunters says contains false allegations about the group.

In that advisory, the FBI described ShinyHunters as a cybercriminal operation specializing in large-scale data theft and extortion, rather than a state-sponsored hacking operation. It accused hackers associated with the group of using threats, harassment and, in some instances, swatting to target victims, while also warning that cybercriminals sometimes exaggerate the scale of data they have obtained.

ShinyHunters has not said what it plans to do with the purportedly stolen information if the FBI refuses its demand. The extent of the intrusion and the number of people affected remain unverified.