The spies were paid informants recruited by the CIA for two espionage rings targeting Iran and Hezbollah, an organization in Lebanon on the U.S. terror list and backed by Iran, ABC News reported Monday.
The CIA hasn't determined how many of its assets were compromised in Iran, but the number could be in the dozens, one current and one former U.S. intelligence official said. In Lebanon, officials said, Hezbollah picked up at least a dozen agents.
"Espionage is a risky business," a U.S. official told ABC News while confirming the loss of the spies in the last six months. "Many risks lead to wins, but some result in occasional setbacks."
Robert Baer, a former CIA officer who worked against Hezbollah in Beirut in the 1980s, said Hezbollah usually executes people caught or suspected of spying.
"If they were genuine spies, spying against Hezbollah, I don't think we'll ever see them again," he told ABC News. "These guys are very, very vicious and unforgiving."
Other current and former officials said the discovery of the two spy rings happened separately.
"If you lose an asset, one source, that's normally a setback in espionage," Baer said. "But when you lose your entire station, either in Tehran or Beirut, that's a catastrophe; that just shouldn't be. And the only way that ever happens is when you're mishandling sources."
One U.S. official offered reluctant respect to Iran's and Hezbollah's dogged efforts to detect and expose U.S. and Israeli espionage, ABC said. Others in the American intelligence community said sloppiness by the CIA also was to blame.