Russian espionage in the United States has occurred since at least the Cold War, and likely well before. According to United States government, by 2007 it had reached Cold War levels.
According to former GRU Colonel Stanislav Lunev, "SVR and GRU (Russia's political and military intelligence agencies, respectively) are operating against the U.S. in a much more active manner than they were during even the hottest days of the Cold War." From the end of the 1980s, KGB and later SVR began to create "a second echelon" of "auxiliary agents in addition to our main weapons, illegals and special agents", according to former SVR officer Kouzminov. These agents are legal immigrants, including scientists and other professionals. Another SVR officer who defected to Britain in 1996 described details about thousand Russian agents and intelligence officers, some of them "illegals" who live under deep cover abroad.
In April 2015, CNN reported that "Russian hackers" had "penetrated sensitive parts of the White House" computers in "recent months." It was said that the FBI, the Secret Service, and other U.S. intelligence agencies categorized the attacks "among the most sophisticated attacks ever launched against U.S. government systems."