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."
Holder also sought to erase concern over the fate of the children of the Russian agents, saying they all were allowed to return to Russia "consistent with their parents wishes" or, in the case of those who were adults or nearly adults, were allowed to make their own choices of where to live.
"The children have all been handled, I think, in an appropriate way," he said.
The seven offspring embroiled in the spy saga ranged in age from a 1-year-old to a 38-year-old architect. In most cases they were born and grew up in the United States, making them U.S. citizens.
On pending terrorism cases, Holder acknowledged "there's a real question" as to whether a terrorist suspect such as self-professed Sept. 11 mastermind Khalid Sheikh Mohammed can face the death penalty if he were to plead guilty before a military commission.
Holder indicated he still favors bringing Mohammed and four alleged accomplices before civilian courts, but that has been met with opposition in Congress and elsewhere. He said no decision has been made on where the trials will be held or whether they would be civilian or military.
He said one roadblock is that Congress has yet to come up with the money for the trials. "The politicization of this issue when we're dealing with ultimate national security issues is something that disturbs me a great deal," Holder said.
Since January, Holder has said that all options are on the table about where to try Mohammed and the four other terrorist suspects.
That includes the possibility of having them go before a military commission in Guantanamo Bay, where they are now held.
"As soon as we can'' resolve those issues, "we will make a decision as to where that trial will occur,'' Holder said.
The attorney general said it is his hope that Congress provides money to move Guantanamo detainees to a new location in Thomson, Ill., where an underused state prison now exists.
Holder also said the closing of the Guantanamo detention camp has become more difficult "because there have been people who have changed their positions" and Congress hasn't agreed to provide the money to relocate the detainees. He said other states have offered to take the prisoners, but did not name any states.
"There is no reason to believe that people held in Guantanamo cannot be held wherever we put them in the United States. Again, very safely and very effectively,'' Holder said.