To the alarm of privacy advocates, the U.S. is making "significant advances" on a crowd-scanning facial-identification surveillance system, the New York Times reports on Wednesday.

The Biometric Optical Surveillance System or BOSS research, the Times reports, "began as an effort to help the military detect potential suicide bombers and other terrorists overseas at 'outdoor polling places in Afghanistan and Iraq,' among other sites, the documents show. But in 2010, the effort was transferred to the Department of Homeland Security to be developed for use instead by the police in the United States."

The system, which may still be years away from use, takes pictures of a subject from different angles, then sends that "3-D signature" to be processed against faces in a database.

News of this facial scanning system comes in the wake of a series of revelations about the NSA's vast surveillance programs.

“This technology is always billed as anti-terrorism, but then it drifts into other applications,” privacy advocate Ginger McCall, who obtained the documents about the developing BOSS system, told the Times. “We need a real conversation about whether and how we want this technology to be used, and now is the time for that debate.”

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