A group of House Democrats has unveiled a new bill that aims to put limits on the use of facial recognition technologies by law enforcement agencies across the United States.

Dubbed the Facial Recognition Act, the bill would compel law enforcement to obtain a judge-authorized warrant before using facial recognition. By adding the warrant requirement, law enforcement would first have to show a court it has probable cause that a person has committed a serious crime, rather than allowing largely unrestricted use of facial recognition under the existing legal regime.

The bill also puts other limits on what law enforcement can use facial recognition for, such as immigration enforcement or peaceful protests, or using a facial recognition match as the sole basis for establishing probable cause for someone's arrest.

If passed, the bill would also require law enforcement to annually test and audit their facial recognition systems, and provide detailed reports of how facial recognition systems are used in prosecutions. It would also require police departments and agencies to purge databases of photos of children who were subsequently released without charge, whose charges were dismissed or were acquitted.

Facial recognition largely refers to a range of technologies that allow law enforcement, federal agencies and private and commercial customers to track people using a snapshot or photo of their faces. The use of facial recognition has grown in recent years, despite fears that the technology is flawed, disproportionately misidentifies people of color (which has led to wrongful arrests) and harms civil liberties, but is still deployed against protesters, for investigating minor crimes and used to justify arrests of individuals from a single face match.

Some cities, states and police departments have limited their use of facial recognition in recent years. San Francisco became the first city to ban the use of facial recognition by its own agencies, and Maine and Massachusetts have both passed laws curbing their powers — though all have carved out exemptions of varying degrees for law enforcement or prosecutorial purposes.