The U.S. State Department's unclassified email system was taken offline over the weekend for security improvements, a scheduled event, but officials conceded suspicious activity had been previously detected, according to media reports.
A department official said "activity of concern" was discovered around the same time the White House's network was attacked in late October, according to the Associated Press, which first reported the incident.
Parts of the department's public website were also shut down, although no classified systems were affected, according to The Washington Post. The shut down, which started late Friday, had been scheduled in order to make improvements to the main unclassified computer network, the AP reported.
The Washington Post reported that officers were using Gmail accounts until service was restored soon.
On Oct. 28 the White House said it detected suspicious activity on the unclassified Executive Office of the President network. The network went down for some time as cybersecurity teams countered the attack, according to officials.
The U.S. was alerted to the breach, thought to have been committed by hackers on behalf of Russia, by an ally, according to the The Washington Post.
Last week, the U.S. National Oceanic and Atmospheric Administration said four websites run by it have been compromised in recent weeks, and the U.S. Postal Service said a data breach potentially compromised the personal information of 800,000 employees.
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