Hackers calling themselves ShinyHunters claim they stole 2 to 3 terabytes of data from the FBI’s jobs portal, including sensitive psychiatric and medical records of FBI staff and applicants.

The group said it breached FBIJobs.gov and took data on almost all FBI agents and job applicants. Reuters reported that documents reviewed by it included medical evaluations, and that the FBI declined to comment on the records.

The FBI said it is aware of a cyber-criminal group claiming to have compromised the portal and is ‘actively and aggressively investigating’ the claims. The bureau has not confirmed that a breach took place or that any data was stolen.

The group gave the FBI a sample of about 5,000 employee records, which included names, phone numbers and home addresses. Some of the data has been independently matched to named individuals, according to reporting.

Earlier this week, ShinyHunters defaced the FBI jobs site with a fake ‘seized’ notice. The applicant portal was taken offline and showed an unavailable message.

The group said the attack was retaliation for an FBI advisory about ShinyHunters published in May. It gave the FBI until September 30 to take down that report.

The investigation is continuing, the FBI said.