More than a dozen undercover agents working for the CIA have been caught in both Iran and Lebanon and the US government fears they will be or already have been executed, ABC News quoted US officials as saying on Monday.
According to the report, the agents were paid informants, hired by the CIA to spy on Iran and Hezbollah in Lebanon.
"Many risks lead to wins, but some result in occasional setbacks," ABC quoted an official as saying. The arrests occurred over the past six months, he added.
The officials gave credit to Iran and Hezbollah for uncovering the two espionage rings, but say sloppy CIA "tradecraft" was also partly to blame for the discovery of the networks.