The civilian panel that oversees the Los Angeles Police Department approved a pilot drone program that the police department says is limited in scope, but viewed by some civil rights organizations as a threat to privacy.

The Los Angeles Board of Police Commissioners voted 3-1 Tuesday in support of the plan. The panel's vote prompted an outcry from opponents, some of whom marched outside the LAPD headquarters and into the intersection of First and Main streets, blocking traffic.

Police declared the gathering an unlawful assembly, ordering the group out of the street. Several protesters were seen being handcuffed and led away by police, although it was unclear if they were only being detained to move them out of the street or if they would be arrested.

The debate over the LAPD's use of drones began about three years ago when the department acquired two of the devices, which it ultimately decided against using in the face of protests from activists. But the department reversed course and in August presented the Board of Police Commissioners with a plan to create a pilot drone program.

Commissioner Cynthia McClain-Hill voted against the program, while Commission President Steve Soboroff, Vice President Matthew Johnson and Commissioner Sandra Figueroa-Villa voted for it. Commissioner Shane Murphy Goldsmith was not present for the vote.

The commission held a meeting two weeks ago, when it approved guidelines for the 1-year pilot program. The guidelines were then posted on the department's website for two weeks to get more public feedback before the final vote.

The commission first heard a presentation on the guidelines in August, and the department held four public meetings to get feedback.

Approval of a drone program -- or unmanned aerial system, as the department calls it -- comes after the Los Angeles County Sheriff's Department Civilian Oversight Commission recently voted 5-4 to call for the grounding of the LASD's drone program, although Sheriff Jim McDonnell said the program would continue.

According to the guidelines the Police Commission approved, drones would be used in a limited capacity, including high-risk tactical operations, barricaded armed suspect responses, hostage rescues, and situations involving threats of exposure to hazardous materials and the need to detect explosive devices.

The drones would not be weaponized or used during surveillance, and their use would have be approved on a case-by-case basis. The commission also added several more amendments before the final vote, including that facial recognition technology would not be used on the drones.

Members of the Stop LAPD Spying Coalition, the Drone-Free LAPD/No Drones, LA! Campaign, the American Civil Liberties Union of Southern California and other civil rights organizations have been vocal about their opposition to the program over concerns that "mission creep" will lead to the devices one day being armed or used for surveillance to infringe on privacy rights.

"Drones represent a significant threat to privacy, one that is very difficult to contain once drones are deployed for any use whatsoever," said Melanie Ochoa, an ACLU staff attorney, at a commission meeting in August.

The groups have also charged that because the emails the LAPD received on the program were overwhelmingly negative, the commission is not interested in the public feedback it is receiving and is just going through the motions.

The Los Angeles City Council cleared the way in June for the city's fire department to begin using drones. A Los Angeles Fire Department report addressed the issue of privacy concerns and said the devices would not be used to monitor or provide surveillance for law enforcement.