(CNN) -- The five Taliban figures who got out of Guantanamo in exchange for U.S. Army Sgt. Bowe Bergdahl's release would be taking an "enormous risk" if they return to the battlefield, Secretary of State John Kerry told CNN in an interview that aired Sunday. "I'm not telling you that they don't have some ability at some point to go back and get involved (in fighting). But they also have an ability to get killed doing that. " Kerry said in his first public comments on the controversial prisoner exchange. Kerry defended the swap and told CNN the former detainees will be monitored closely -- and not just by officials in Qatar, where they were flown after being released. He wouldn't say who else will be watching, but he said the United States is confident the conditions of their release will be honored.
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NEW: Taliban source: Bergdahl did not convert to Islam, learned to speak Pashto
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NEW: Law enforcement official: Threats to Bergdahl family came via e-mail
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John Kerry says released Taliban figures will be monitored
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If they turn to violent ways, they could die violent deaths, he says
Nine songs celebrating the release of the five Taliban detainees were posted to a @placeholder website Saturday.