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Facial recognition is used in tech products to do things like unlock your phone, add cool camera effects and help you play with your robot dog. But other applications of the technology aren't always as innocent.

That's why the American Civil Liberties Union has teamed up with more than 85 human rights groups to ask big tech companies not to provide face surveillance technology to the US government. The coalition sent letters to Microsoft, Amazon and Google to make sure its stance on the issue was heard.

You may've heard stories about the Chinese government experimenting with facial recognition technology to monitior citizens. The technology has also had a mixed track record when it comes to its use by law enforcement in the west. A study from May 2018 found that facial recognition tech used by the UK's Metropolitan Police was inaccurate in 98 percent of cases. But that hasn't stopped the US Department of Homeland Security from testing facial recognition around the White House.

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The ACLU and the coalition of groups want to ensure that big tech companies don't allow the US government to use their facial recognition technologies to limit human rights. The ACLU says facial recognition "gives the government new power to target and single out immigrants, religious minorities and people of color in our communities" and that "systems built on face surveillance will amplify and exacerbate historical and existing bias."

Some of the petitioned companies have already spoken on the implications of facial recognition. Microsoft called for regulation of the technology so it isn't used to "exacerbate social issues." Google has said it won't make general-purpose facial recognition programming tools available "before working through important technology and policy questions."

Meanwhile, Amazon has taken heat for filing patents that discuss using facial recognition in smart doorbells to alert police about suspicious individuals, and for selling its Rekognition tech to law enforcement.

Microsoft, Amazon and Google didn't immediately respond to a request for comment on the coalition's letter.

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