SAN JOSE (CBS/AP) — For years, top officials of the Bush and Obama administrations dismissed fears about secret government data-mining by reassuring Congress that there were no secret nets trawling for Americans’ phone and Internet records.

But on Friday at a press conference in San Jose, President Barack Obama himself acknowledged the existence of such programs while giving the government’s standard rationale to ease fears that Americans’ privacy rights are being violated.

Obama told reporters that sifting through mountains of data could potentially lead investigators to terrorists.

Obama’s comments marked the first time a U.S. president publicly acknowledged the government’s electronic sleuthing on U.S. citizens. They came in response to media revelations and published classified documents that detailed the government’s secret mass collection of phone and Internet communications.

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