But Oleg Kalugin, who once managed spy operations out of the Soviet Embassy in Washington, said Snowden's significance has been "exaggerated," and the Russians likely already knew much of what he revealed.
"Well, he did collaborate, obviously, but I'm not sure what he provided was not known to the Russians before he came," Kalugin told the Washington Examiner. "He may have confirmed something, but I don't believe they were informed for the first time by Snowden."
House Intelligence Committee Chairman Mike Rogers has accused Snowden of working with Russian intelligence for months.
"This was a thief, who we believe had some help, who stole information the vast majority had nothing to do with privacy," the Michigan Republican told NBC's "Meet the Press" in January. "Our Army, Navy, Air Force, Marines have been incredibly harmed by the data that he has taken with him and we believe now is in the hands of nation-states," adding that "there's a reason he ended up in the hands, the loving arms, of an FSB agent in Moscow."
FSB is a counter-intelligence agency "that occupies the former headquarters of the KGB on Lubyanka Square in downtown Moscow."
Meanwhile, the Wall Street Journal reported Monday that the Russian military was able to evade U.S. intelligence while planning its invasion of Crimea, leading many to speculate that Snowden's revelations had made it possible. The story did not mention Snowden.
"Some U.S. military and intelligence officials say Russia's war planners might have used knowledge about the U.S.'s usual surveillance techniques to change communication methods about the looming invasion," the Journal reported. "U.S. officials haven't determined how Russia hid its military plans from U.S. eavesdropping equipment that picks up digital and electronic communications."
Kalugin said he doubted Snowden's revelations made it easier for Russia to prepare for the Crimea invasion.
"Well, intelligence is often behind," Kalugin chuckled. "Don't forget that the Soviets and the Russians, for decades, had access to some American information not for the general public and I don't think they found anything extraordinary in Snowden's papers."
When asked if he thought Russian intelligence still has spies in the United States, Kalugin said that he didn't know for sure.
"I mean, all the time [that] I'm aware of they always had human sources inside the United States, and elsewhere, not only in the United States," he said. "You never know who knows what. You don't have to have human sources inside. Technology alone helps break codes and control, I mean, monitor everything."