Personal information for roughly 14,000 past and current Energy Department employees was compromised in a recent hacking attack, the department said in a memo to staff.

Personally identifiable information, such as Social Security numbers and names, were pilfered in the July attack, the DOE said this week.

The DOE declined to comment on from where the attack might have originated.

In the memo, the department said it was working with its internal cybersecurity office; the Office of Health, Safety and Security; and the Office of Inspector General and other federal law enforcement officials to determine the source of the incident.

Read below for the full DOE memo:

The Department of Energy has confirmed a recent cyber incident that occurred at the end of July and resulted in the unauthorized disclosure of federal employee Personally Identifiable Information (PII).