06/06/2013 07:08 pm ET

Chinese Hacked Obama, McCain Campaigns, Took Internal Documents, Officials Say

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The U.S. secretly traced a massive cyberespionage operation against the 2008 presidential campaigns of Barack Obama and John McCain to hacking units backed by the People’s Republic of China, prompting high level warnings to Chinese officials to stop such activities, U.S. intelligence officials tell NBC News.

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