The FBI and Department of Homeland Security said on Saturday that ongoing investigations around reported drone sightings over New Jersey have found many reports are, in fact, manned aircraft. The FBI has been investigating hundreds of reports of drones operating at night since mid-November,

Officials sound alarm over reports of the strange sights—seen over New Jersey, New York, Maryland and Pennsylvania—with one asking for a “limited state of emergency.”

A series of drone sightings over New Jersey and near U.S. military installations that began in mid-November has residents concerned and lawmakers demanding answers as their origins and purpose remain unknown.