The Federal Aviation Administration has authorized the use of hundreds of drones in U.S. airspace in recent years but offered few details on who is operating them.

The Qube, an unmanned aerial vehicle developed by AeroEnvironment for public safety agencies. (Gary Winterboer/Courtesy AeroEnvironment)

“Drones give the government and other unmanned aircraft operators a powerful new surveillance tool to gather extensive and intrusive data on Americans’ movements and activities,” said Jennifer Lynch, attorney for the San Francisco-based Electronic Frontier Foundation, which filed the suit in U.S. District Court in Northern California. “As the government begins to make policy decisions about the use of these aircraft, the public needs to know more about how and why these drones are being used to surveil United States citizens.”

The FAA regulates the operation of drones domestically, and only occasionally grants permission to the federal and local agencies seeking authority to fly unmanned vehicles. But those decisions, civil liberties groups point out, are based on safety concerns, not privacy concerns.

With growing interest in drones and their applications — to patrol U.S. borders, to search for criminal suspects, even to track the spread of forest fires — privacy advocates are now showing increasing concern about the policies guiding their use.

“In my mind, the first step is to get the information from the FAA about who has authorization,” Lynch said in an interview. “We don’t really know very much right now.”

The EFF, which advocates on behalf of “digital rights,” filed a Freedom of Information Act request to the FAA in April. According to the lawsuit, the agency has yet to process or release records in response.

A spokesman for the FAA, Les Dorr Jr., declined comment on the suit.

The Defense Department, the Department of Homeland Security and the FBI are among the agencies that have used drones domestically. Some drone manufacturers and academic institutions have also been granted authority for research or training purposes.

But the FAA is expected to soon formulate new rules on the use of lightweight drones — perhaps by early this spring, Dorr said.

That has privacy advocates worried that the agency could dramatically expand the skies for aircraft with sophisticated surveillance capabilities. And it has them interested in knowing who will be flying them.

“My feeling and the EFF’s feeling is that this information should be public,” Lynch said.

Staff writer Peter Finn contributed to this post.