The State Department this weekend shut down its entire unclassified email system amidst suspicions of a computer hack.
A senior department official on Sunday told the Associated Press that "activity of concern" was detected in the system—around the same time the White House computer network was targeted.
In recent weeks, the U.S. Postal Service and National Weather Service also suffered attacks, making the State Department the fourth government agency to announce a recent breach.
The State Department moved on Friday to shut down its worldwide email, "as part of a scheduled outage of some of its Internet-linked systems to make security improvements." None of its classified systems were affected.
The system is expected to be back up "in the near future," the AP reported, which probably means today or tomorrow.
The State Department did not immediately respond to PCMag's request for comment.
Nextgov suggested that the same hackers who infiltrated the White House system earlier this fall are also to blame for the State Department attack; perhaps those backed by a nation state like Russia or China.