While they passed along no U.S. secrets, the 10 Russian sleeper agents involved in the spy swap posed a potential threat to the U.S. and received "hundreds of thousands of dollars" from Russia, Attorney General Eric Holder said.
"Russia considered these people as very important to their intelligence-gathering activities," he told CBS' "Face the Nation" in an interview broadcast Sunday.
He defended the decision to allow the 10 to return to Russia in exchange for the release of four Russian prisoners accused of spying for the West because the swap presented "an opportunity to get back ... four people in whom we have a great deal of interest."