An anonymous reader writes: At a hearing today before Congress, FBI director Robert Mueller confirmed that the agency is using unmanned drones for surveillance within the U.S. Senator Chuck Grassley asked, 'Does the FBI own or currently use drones and for what purpose?' Mueller replied, 'Yes, for surveillance.' Grassley then asked, 'Does the FBI use drones for surveillance on U.S. soil?' Mueller said, 'Yes, in a very, very minimal way, and seldom.' With regard to restricting the use of drones to protect citizens' privacy, Mueller said, 'It is still in nascent stages but it is worthy of debate and legislation down the road.' According to The Guardian, 'Dianne Feinstein, who is also chair of the Senate intelligence committee, said the issue of drones worried her far more than telephone and internet surveillance, which she believes are subject to sufficient legal oversight.'