The Chinese government worked to weaken CIA spying operations by killing or imprisoning more than a dozen informants over two years, The New York Times reported Saturday.

American officials told the newspaper that the intelligence breach lasted from 2010 through the end of 2012, essentially undoing the spy network that had been built over many years.

Between 18 and 20 CIA sources were imprisoned or killed by the Chinese, two former senior U.S. officials told the Times. An official said one informant was shot in front of his colleagues outside of a government building in an apparent gesture to intimidate other potential informants.

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Officials say inside information about the Chinese government was the best it had ever been in 2010, however by the end of year the information appeared to stop coming through.

The FBI and CIA opened a joint investigation based out of northern Virginia. A former senior official told the Times the operation was code named "Honey Badger."

American officials clashed over the cause of the damage, however it is still unknown whether the Chinese hacked the a CIA communications system or if there was a mole.

The report comes as the U.S. government struggles to deal with documents published by WikiLeaks last year and investigates ties between President Trump's campaign and Russia, which the U.S. intelligence community has said tried to infer in the election.

China has recently stepped up its spying practices. Last year an FBI employee pleaded guilty to relaying sensitive technology information to the Chinese government in return for money, hotels and prostitutes.