Robots are being used against the Bay Area’s homeless population.

According to a recent report by The San Francisco Business Times, autonomous crime-fighting machines known as K9s are patrolling city sidewalks to deter homeless people from setting up tent encampments. The San Francisco SPCA (Society for the Prevention of Cruelty to Animals) started using these robots near its Mission campus in early November as a way to prevent sidewalk camps and other issues, such as discarded needles and car break-ins.

The S.F. SPCA president claims that since the organization began utilizing K9, they’ve seen a huge decrease in crime; however, the city doesn’t seem too thrilled about this fleet of robot security guards. Earlier this month, San Francisco officials ordered the SPCA to keep the machines off the sidewalks or risk a $1,000 daily penalty for operating without a permit. The S.F. SPCA president claims the benefits of these robots outweigh any potential inconvenience, like obstructing foot traffic.

"We weren’t able to use the sidewalks at all when there’s needles and tents and bikes, so from a walking standpoint I find the robot much easier to navigate than an encampment," S.F. SPCA president Jennifer Scarlett told the Business Times.

The K9 was created by a California-based startup called Knightscope, which rents out the robots for around $6 an hour. Many companies like Uber and Microsoft have used these machines to monitor their parking lots and offices in the hopes of preventing crime. The machines are 5-feet tall, weigh 400 pounds, and can travel up to 3 miles per hour. Though they aren’t built to intervene during crimes, they are equipped with cameras, lasers, thermal sensors, and GPS to alert authorities about any illegal activity.

While S.F. SPCA claims the robots are improving the safety of the area, many people have criticized the move as another way to unfairly criminalize homelessness amid a backdrop of rising rents and gentrification.