The International Association of Chiefs of Police released recommendations on Thursday for the use of unmanned drones by police agencies.
Police can use drones to provide intelligence to officers on the ground, to track suspected criminals or to find children who have gone missing. But the group said that police agencies should be transparent about how they use drones and take steps to avoid invading people's privacy.
The chiefs "strongly discouraged" agencies from equipping drones with weapons, saying the effectiveness of weapons is doubtful and would likely cause a public backlash against the technology.
They also recommended that officers obtain a warrant if the use of the drone would intrude upon someone's reasonable expectation of privacy.
The group said police should delete images that are not required for investigations and should notify the public about the use of a drone. Drones should be painted with a high-visibility color except for situations when stealth is necessary, according to the guidelines.
Police should keep careful records of drone flights and misuse should result in "strict accountability," the group said.
The American Civil Liberties Union (ACLU) applauded the police chiefs for issuing the guidelines, but said laws governing the use of drones are necessary.
"[W]e don’t think these recommendations go far enough to ensure true protection of privacy from drones," the ACLU wrote. "We also think protections need to be put into law, not merely promulgated by the police themselves."