More than a dozen spies working for the CIA have been caught in Iran and Lebanon, and US officials fear they may face execution, ABC News reported Monday.
The report is based on information from four current and former US officials with connections to the intelligence community.
"Espionage is a risky business," a US official told ABC News. "Many risks lead to wins, but some result in occasional setbacks."
More from GlobalPost: Syrian activists mock Hezbollah leader
The spies, who have been caught over the past six months, were part of two espionage rings targeting Iran and the organization Hezbollah, which is based in Beirut. The spies were following Iran's nuclear program and Hezbollah's activities with regard to Israel.
There is a concern among some current and former US officials that the spies may be executed or have already been killed.
"If they were genuine spies, spying against Hezbollah, I don't think we'll ever see them again," former CIA officer Robert Baer told ABC News. "These guys are very, very vicious and unforgiving."
More from GlobalPost: Top 10 ways the US bullies Iran
He said Hezbollah typically executes suspected spies.
CIA officials have been working to protect their current spies in Lebanon, the Associated Press reported.
The Lebanon crisis is the latest mishap involving CIA counterintelligence, the undermining or manipulating of the enemy's ability to gather information. Former CIA officials have said that once-essential skill has been eroded as the agency shifted from outmaneuvering rival spy agencies to fighting terrorists. In the rush for immediate results, former officers say, tradecraft has suffered.