(CNN) The nation's largest police force has unveiled a fleet of drones that will be used in hostage situations and search and rescue operations, but a civil rights group worries the drones might be used to invade privacy.

The New York City Police Department said Tuesday the drones in its unmanned aircraft system program will be deployed in incidents involving hazardous spills and used to document crime scenes and collisions. They will also monitor pedestrians and traffic at large events.

The unmanned aerial vehicles will help the NYPD gather key information as situations unfold before officers arrive, lessening the danger to them, the agency said.

The New York Civil Liberties Union said the department's drone policy isn't restrictive enough to protect the privacy of New York residents. An NYPD commander said the agency is aware of the concerns about the drone program.

Drone technology joins a long list of tools at the NYPD's disposal during emergency situations. All of which help the men and women in blue uphold their mission — to protect every New Yorker. pic.twitter.com/6wluH2044O — Chief Terence Monahan (@NYPDChiefofDept) December 5, 2018

"So, let me be clear, NYPD drones will not be used for warrantless surveillances," Chief of Department Terence Monahan told reporters. "NYPD drones will be used to save lives and enhance our response in emergency situations."

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