Emerging tech is making it more efficient and inexpensive for police across the country to scale up their surveillance operations.

Drones, facial recognition, and algorithm-driven policing are a few of the many technologies aiding police operations.

The surveillance tech has reportedly been deployed across the US as protests sweep the country following the death of George Floyd.

Human rights advocates have raised the alarm about new policing technologies, highlighting their potential threats to privacy, free speech, and due process.

Visit Business Insider's homepage for more stories.

Emerging technology is giving police departments new ways to track suspects and head off possible crimes. It's also rapidly expanding the scope of police surveillance of civilians.

Police across the country are using tech to widen the scope of people and platforms that they monitor. This surveillance is rarely publicized given the sensitive nature of police investigations, but details of police tactics have regularly surfaced through lawsuits, public records disclosures, and success stories touted by police departments as examples of successful crime prevention.

Law enforcement agencies have made full use of high-tech surveillance tools as protests sweep the country following the death of George Floyd. A predator drone operated by Customs and Border Patrol circled above protesters in Minneapolis Friday, Motherboard first reported. Police have also reportedly dug into the smartphones of arrested protesters to glean their personal information.

Human rights advocates have raised the alarm about the acceleration of police surveillance using new technology. A report published by the Brennan Center for Justice this week compiles tactics used by the New York Police Department, highlighting their potential threats to privacy, free speech, and due process.

[ Read more: AI could be the key to ending discrimination in hiring, but experts warn it can be just as biased as humans ]

While this technology is relatively new, it's already widely used across the US. Databases of people's faces compiled by local police departments now contain over half of American adults, according to a study by researchers at Georgetown.

Some cities have begun to take action to regulate police use of technology for surveillance. San Francisco became the first city to ban the use of facial recognition software by police in May, and the New York City Council is currently weighing a bill to force the NYPD to publicly disclose their tactics involving surveillance technology.

But in the absence of such regulation, police tactics are largely opaque, and there isn't much court precedent for how transparent police departments are obligated to be regarding their surveillance methods.

Here's what we do know about how police departments across the US are using technology for surveillance.