Intruders are trying to crash the White House inside and out. While the Secret Service tries to clamp down on people jumping the fence along Pennsylvania Avenue, federal authorities have been battling gatecrashers of the cyber variety.

Hackers who may have been working for the Russian government succeeded in breaching unclassified networks at the White House earlier this month, leading to disruptions as U.S. authorities moved to secure the building's computers.

A White House official confirmed Wednesday morning that authorities "identified activity of concern on the unclassified Executive Office of the President network."

"Any such activity is something we take very seriously. In this case, we took immediate measures to evaluate and mitigate the activity," the official said. "Our actions are ongoing, and some have resulted in some temporary outages and loss of connectivity for our users."

The computers and systems were not damaged and the hackers did not reach more tightly secured secret material. It was the response to the breach, and not the cyberattacks themselves, that caused "temporary disruptions to some services," the official said. A White House reporter for Roll Call noted late last week in a pool report and Tuesday night on Twitter that the building's email system had been down "for extended periods."

Russia and China have repeatedly been accused of launching cyberattacks against U.S. government and military networks. In this case, the Russian government is suspected, according to The Washington Post, which cited sources in reporting that "the nature of the target is consistent with a state-sponsored campaign."

The breach was first discovered two to three weeks ago after the U.S. was alerted to it by an ally, The Post reported on Tuesday night.