State Department
The Harry S. Truman Building at the Department of State in Washington, D.C. The department is weeding out malware. Reuters

The U.S. State Department’s IT team is going to have a busy weekend as they try to weed out malware that has invaded the unclassified portion of the email system used by American foreign relations officials. Described to ABC News by department spokeswoman Jen Psaki as “a planned outage of some Internet-linked systems,” the work is expected to last at least a couple of days.

Officials announced earlier this week the discovery of the worst cyber-breach against a federal agency, believed to have been a play by Moscow to tap into State Department communications. The malware is believed to have existed on government servers for much of the past year.

“There has been no compromise of any of the Department's classified systems, nor of our core financial, consular and human resource systems,” the State Department said in an official statement regarding the sneaky software.

News of the breach was largely overlooked this week by the media as they focused on the controversy surrounding former Secretary of State Hillary Clinton’s use of a private email server to conduct official business. On Wednesday, Clinton dismissed suggestions she compromised classified communications by using her private email from a server located in her home.

The discovery, as well as Clinton’s use of an at-home email server, underscores increased concern over the security of U.S. government communications amid a growing number of cyberattacks on government and private companies originating in China, Russia and Eastern Europe.

This isn’t the first time the State Department has dealt with malware attacks. In November, it conducted a similar series of repairs to deal with a cyberattack that took place a month earlier. The White House, the U.S. Postal Service and the National Weather Service also reported similar attacks at the time.