The CIA has asked its frontline spies around the world to beef up their operational security after dozens of informants have been imprisoned, killed, or otherwise compromised in recent years, according to the New York Times.

The specific number of human sources imprisoned or executed by rival services was contained in a cable issued last week from top US counterintelligence officers to every agency station and base, according to the New York Times.
 

The dossier blames case officers in charge of recruiting new informants for a variety of difficulties, including bad tradecraft, underestimating foreign agencies' counterintelligence capabilities, and focusing on recruitment without paying attention to potential threats. It goes on to say that police should focus on those concerns as well as bringing in new sources.

China has reportedly become particularly effective in tracking down and disrupting US surveillance networks in recent years, according to sources. The New York Times reported in 2017 that Beijing has executed at least 12 suspected informants and imprisoned several more in one such case.