The US Department of State shut down its unclassified email system over the weekend after a suspected breach, according to the Associated Press.
The activity detected by State Department technicians, which the Department calls "activity of concern," actually dates back to October, around the time of. Other government institutions, including the US Postal Service and National Weather Service, have reported similar attacks. It is not clear whether the attacks are related.
A State Department official who spoke to the AP insisted that classified systems were unaffected. In addition to the unclassified email system, access to the Department's public web sites from its unclassified network was shut down.
The AP reports that the Department expects to issue a statement on the matter Monday or Tuesday, after security improvements have been put in place.
According to the Washington Post, the shutdown has resulted in State Department officers using Gmail accounts for unclassified communications.