Documents obtained by the ACLU of Northern California have shed new light on Rekognition, Amazon’s little-known facial recognition project. Rekognition is currently used by police in Orlando and Oregon’s Washington County, often using nondisclosure agreements to avoid public disclosure. The result is a powerful real-time facial recognition system that can tap into police body cameras and municipal surveillance systems.

According to further reporting by The Washington Post, the Washington County Sheriff pays between $6 and $12 a month for access to Rekognition, which allows the department to scan mug shot photos against real-time footage.

The most significant concerns are raised by the Orlando project, which is capable of running real-time facial recognition on a network of cameras throughout the city. The project was described by Rekognition project director Ranju Das at a recent AWS conference in Seoul.

“This is an immediate response use case,” Das told the crowd. “There are cameras all over the city [of Orlando]. Authorized cameras are streaming the data to Kinesis video stream…. We analyze that data in real time and search against the collection of faces that they have. Maybe they want to know if the mayor of the city is in a place, or there are persons of interest they want to track.”

For the ACLU, that capability raises significant civil liberties concerns. “By automating mass surveillance, facial recognition systems like Rekognition threaten this freedom, posing a particular threat to communities already unjustly targeted in the current political climate,” the group said in a statement. “People should be free to walk down the street without being watched by the government.”

Introduced in November 2016 as part of the Amazon Web Services cloud, Rekognition is also used by consumer services like Pinterest and C-SPAN for object recognition and analytics. Most recently, it provided the backend for a Sky News project that used facial recognition to identify guests at the royal wedding. Motorola Solutions, a popular supplier of police body cameras, is also a client.

The ACLU has already joined with other groups to call on Amazon to cease providing facial recognition services to law enforcement and other government agencies. “We demand that Amazon stop powering a government surveillance infrastructure that poses a grave threat to customers and communities across the country,” the groups said in an open letter addressed to CEO Jeff Bezos. “Amazon should not be in the business of providing surveillance systems like Rekognition to the government.”

In a comment to The Verge, Amazon emphasized that the company suspends any accounts found to be violating the law or otherwise using its services irresponsibly. “As a technology, Amazon Rekognition has many useful applications in the real world,” an Amazon representative said in a statement. “Our quality of life would be much worse today if we outlawed new technology because some people could choose to abuse the technology.”

Update 12:24PM ET: Updated to include Amazon statement.