Drone surveillance in the United States does not require a warrant, but the practice remains limited, the FBI told Sen. Rand Paul, R-Ky., in a letter after he placed a hold on James Comey’s nomination to be the new FBI director.

“[T]he FBI does not, and has no plans to use [unmanned aerial vehicles] to conduct general surveillance not related to a specific investigation or assessment,” Stephan Kelly, the assistant director at the FBI’s Office of Congressional Affairs, wrote Paul.

Kelly said that UAVs, or drones, have only been used for surveillance in the United States 10 times since 2006, in cases related to “kidnappings, search and rescue operations, drug interdictions, and fugitive investigations.”