Dozens of reported drone sightings in the skies above New Jersey have concerned lawmakers and local officials and left them searching for answers.

Gov. Philip D. Murphy said there were nearly 50 reported sightings in a single night over the weekend. And since mid-November, drones have been reported in at least 10 counties in New Jersey and in parts of New York City.

The Federal Aviation Administration has temporarily banned drones from flying over a New Jersey golf course owned by President-elect Donald J. Trump and from the skies over Picatinny Arsenal, an Army facility in Morris County.

Eleven drones have been spotted near the arsenal by security guards and police officers since Nov. 13, according to Timothy Rider, a public affairs specialist for the facility. Mr. Rider added that the “increased drone activity” was not the result of military operations related to the base.

The F.B.I. cannot explain the sightings and has not been able to identify where the reported drones are coming from, or going. “We just don’t know, and that’s the concerning part,” Robert Wheeler, the assistant director of the bureau’s Critical Incident Response Group, said in testimony to Congress on Tuesday.

But Mr. Wheeler said that the authorities had no reason to believe that sightings posed a threat to public safety. Mr. Murphy said the same thing last Thursday.