The new tool, called Mobile Fortify, uses the CBP system which ordinarily takes photos of people when they enter or exit the U.S., according to internal ICE emails viewed by 404 Media. Now ICE is using it in the field.

Immigration and Customs Enforcement (ICE) is using a new mobile phone app that can identify someone based on their fingerprints or face by simply pointing a smartphone camera at them, according to internal ICE emails viewed by 404 Media. The underlying system used for the facial recognition component of the app is ordinarily used when people enter or exit the U.S. Now, that system is being used inside the U.S. by ICE to identify people in the field.

The news highlights the Trump administration’s growing use of sophisticated technology for its mass deportation efforts and ICE’s enforcement of its arrest quotas. The document also shows how biometric systems built for one reason can be repurposed for another, a constant fear and critique from civil liberties proponents of facial recognition tools.

“Face recognition technology is notoriously unreliable, frequently generating false matches and resulting in a number of known wrongful arrests across the country. Immigration agents relying on this technology to try to identify people on the street is a recipe for disaster. Congress has never authorized DHS to use face recognition technology in this way, and the agency should shut this dangerous experiment down,” Nathan Freed Wessler, deputy director of the American Civil Liberties Union’s Speech, Privacy, and Technology Project, told 404 Media in an email.