Russian espionage agents have managed to infiltrate the White House’s unclassified computer network, according to the Washington Post.

“In the course of assessing recent threats, we identified activity of concern on the unclassified Executive Office of the President network,” an anonymous White House official told the Post. “We took immediate measures to evaluate and mitigate the activity. . . . Unfortunately, some of that resulted in the disruption of regular services to users. But people were on it and are dealing with it.”

The Secret Service, the FBI and the National Security Agency are all working in the class, which appears to have happened in the last few weeks. The official did not state the extent of the breach or what data was taken, but said the breach did not affect the classified portion of the White House network.

When the attack was discovered, VPN access was temporarily shut off, but the White House’s email system stayed up.

The incident is consistent with other hacking operations apparently instigated by the Russian government. Targets have included NATO, defense contractors and the government of Ukraine.

Even though the Cold War officially ended over two decades ago, affairs between the U.S. and Russia are still rather tense, as seen in the Ukraine crisis this year.

Back at home, the Secret Service is still facing criticism after an intruder managed to get into the White House through an unlocked door in September.

As one of the world’s most powerful locations, it’s not surprising the White House would be a target for hacking. It’s also not the first time Russia has managed to hack American computers. The Russian intelligence agency broke into the military’s classified network in 2008. The attack led the government to form the U.S. Cyber Command to help guard important systems against these kinds of attacks.