• The move enabled the Russians to evade being surveilled and to communicate with human sources. It also gave them the opportunity to collect information about their pursuers. And it reportedly prompted concerns among officials that there was a Russian asset within the US intelligence community.
  • Yahoo News reported that Russia's hack of the FBI's communication systems was a key reason why former President Barack Obama's administration kicked out 35 Russian diplomats and shuttered two Russian diplomatic facilities in December 2016.
  • Russia and the US have ramped up their counterintelligence and cybersecurity operations against one another in recent years and tensions between the two countries continue to mount.
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The Russian government hacked into the FBI's communication system to stop the bureau from being able to track Russian spies working in the US, Yahoo News reported in a bombshell investigation published Monday.

The US first became aware of "the full gravity" of Russia's ability to breach certain types of secure communications and track devices used by FBI surveillance teams in 2012, the report said. In addition to fearing the Russians may have gained access to US intelligence channels, officials also believed Russian spies could locate undercover FBI surveillance teams and the substance of FBI communications.

That would not only have enabled the Russians to evade being surveilled and communicate with human sources, it also gave them the opportunity to collect information about their pursuers, Yahoo reported . It also prompted concerns among officials that there was a Russian asset lurking within the US intelligence community.

The Russians first breached the FBI's communication systems in 2010, after the arrest and exposure of a group of Russian spies in the US. That year, the FBI began investigating Russia's efforts to recruit US assets, and one of their foremost targets was Carter Page, who later served as a foreign policy aide on President Donald Trump's campaign.

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The FBI informed Page in 2013 that the Russians were trying to cultivate him, but Page ignored their warnings and even publicly boasted about his connections to high-ranking Russian government officials.

The Russians are also said to have breached the backup communication channels the FBI used, which one former senior counterintelligence official told Yahoo News the US took "extremely seriously."

The investigation found that Russia's hack of the FBI's communication systems was a key reason why former President Barack Obama's administration kicked out 35 Russian diplomats and shuttered two Russian diplomatic facilities in December 2016.

Obama announced that the measures were being taken in retaliation for Russia's interference in the 2016 election, but Yahoo News reported that the US also wanted to shut down those two compounds because they were critical to Russia's efforts to intercept FBI communications.

Read more: Putin just asked Interpol to find a Russian spy in the US, days after the media revealed his whereabouts

Both Russia and the US have ramped up their counterintelligence and cybersecurity operations against one another in recent years as tensions between the two countries continue to mount.

In particular, the US has recently targeted Russia's electrical grid and placed potentially crippling malware within the Russian system, The New York Times reported in June. Power grids have long been the focus of cyberattacks, but the US's operation is the most aggressive yet and is meant to serve as a warning to Russia, as well as position the US to carry out additional cyber attacks in the event of a conflict with Moscow.

The Times cited two administration officials as saying there was "broad hesitation" to brief Trump in much detail about the operation, in part because of concerns over how Trump would react, or that he would shut down the operation or discuss it with foreign officials.

The fears came after Trump in 2017 revealed classified information to two Russian officials in an Oval Office meeting. That disclosure contributed to the US's decision to extract a top CIA asset in Russia shortly after, CNN reported last week.

Other US media outlets subsequently published key identifying details about the asset , and Russian state-sponsored media later said it had a name for the intelligence operative. Shortly after, the Russian government filed a request with Interpol for more information about the spy.

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