Three days ago, Governor Phil Murphy (D) attempted to soothe worries that the mysterious drones flying in New Jersey airspace posed a threat to public safety. But growing concern – and additional sightings – moved Murphy to write to President Joe Biden on Thursday, emphasising the need for more federal resources.

Murphy wrote that “existing laws limit the ability of state and local law enforcement to counter” the drones, also referred to as unmanned aircraft systems. Murphy stressed that the drones have “raised more questions than answers” and have led to the circulation of conspiracy theories across the internet as people search for explanations.

Action to address the drones, Murphy added, rests “squarely on the shoulders of the federal government”.

The New Jersey State Police have received reports of drones since November 18, Murphy wrote. The sightings have been spotted near homes, businesses, military research facilities and President-elect Donald Trump’s golf course in Bedminster.

Federal investigators said they don’t have answers yet but added they don’t believe the drones pose a public threat. The FBI’s Newark Field Office and the New Jersey State Police have been investigating the reports for about a month, and the Federal Aviation Administration has imposed drone flight restrictions near Bedminster and Picatinny while authorities investigate.