U.S. intelligence agencies mining data of at least 9 Internet companies – Barbara Starr reports

FROM CNN WIRES:

America's top intelligence official on Thursday night challenged news reports claiming Facebook posts, Gmail messages and more have been intercepted for years in a vast data-mining operation, saying the reports "contain numerous inaccuracies."

The Guardian, a British newspaper, and the Washington Post reported Thursday that U.S. intelligence agencies had access to the central servers of nine of the country's biggest technology firms including Microsoft, Apple, Google, Yahoo and Facebook.

The Post reported the program - called PRISM - underwent "exponential growth" since its founding in 2007. In fact, the newspaper said the program has become the leading source of raw material for the National Security Agency, the secretive U.S. intelligence operation that monitors electronic communications.

READ MORE: Top U.S. intel official challenges reports that spy agencies mined Internet data