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,

A large number of mysterious drones have been reported flying over parts of New Jersey and the East Coast in recent weeks, sparking speculation and concern over who sent them and why.New Jersey Gov. Phil Murphy wrote to President Joe Biden asking for answers.

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.”