Top government officials have been testifying before Congress this week about the government’s secret surveillance program. Much of the discussion has centered on the NSA and FBI and their requests for information from Internet providers and phone companies. But FBI Director Robert Mueller was also asked about whether the government uses drones for surveillance. Mueller said yes, though it is extremely rare. He also suggested that more discussion is needed on the use of drones domestically.

Here’s the Guardian with the details:

The bureau’s director, Robert Mueller, said it used drones to aid its investigations in a “very, very minimal way, very seldom… It is still in nascent stages but it is worthy of debate and legislation down the road,” said Mueller, in response to questions from Hawaii senator Mazie Hirono.

Peter Singer at the Brookings Institution says its Mueller’s comments about the drone debate that stand out the most.

“My concern is that we keep — again and again — hearing officials say, ‘yes, that’s a debate we ought to have,'” Singer says. “But they are describing a need for that debate after a decision has been made.”

Singer says despite legislators’ request for a real debate, Congress is challenged by the speed of technological advancements — and a precedent of reacting to outcry instead of being proactive.