Earlier, reports about surveillance aircraft flying over Baltimore emerged in the media and social networks. The overhead surveillance program involved at least two planes, according to reports.
"The aircraft were specifically used to assist in providing high-altitude observation of potential criminal activity to enable rapid response by police officers on the ground," FBI spokeswoman Amy Thoreson said on Wednesday, as quoted by the Baltimore Sun daily.
She added that the move was approved at a "high level."
On April 27, violent riots erupted in Baltimore, Maryland, after the funeral of 25-year-old African-American Freddie Gray, who died of spinal injuries nearly a week after he was detained by police.
The rioters looted stores, injured 20 police officers, destroyed 15 buildings and set 144 cars on fire. It forced Maryland’s Governor Larry Hogan to declare a state of emergency and deploy 5,000 Maryland National Guard troops to quell the riots.
Gray’s death came after a string of mostly African-Americans killings at the hands of police over the past year, triggering massive protests against police brutality and unaccountability throughout the United States.