Up to 20 CIA informants were killed or imprisoned by the Chinese government between 2010 and 2012, the New York Times reports, damaging US information-gathering in the country for years.
It is not clear whether the CIA was hacked or whether a mole helped the Chinese to identify the agents, officials told the paper.
They said one of the informants was shot in the courtyard of a government building as a warning to others. The CIA did not comment on the report.
Four former CIA officials spoke to th paper, telling it that information from sources deep inside the Chinese government bureaucracy started to dry up in 2010. Informants began to disappear in early 2011.
The CIA and FBI teamed up to investigate the events in an operation one source said was codenamed Honey Badger.