FBI Director James Comey said the agency used surveillance aircrafts above Ferguson, Missouri, last year to help local law enforcement keep track of unrest on the ground.
Comey did not elaborate during a House Judiciary Committee hearing on Thursday.
But in response to questioning, he said the FBI uses airplanes during investigations of specific suspects in criminal, terrorism and espionage investigations and to help local police during emergencies.
He said the FBI never uses its planes for mass surveillance. When planes are flown above large crowds at the request of local law enforcement, the purpose is to look for violence and trouble spots.
The FBI has previously acknowledged that a plane was flown above riots in Baltimore last April.
Comey said the FBI generally doesn't think warrants are required.
