In recent days, the sightings have led to the temporary closures of a Stewart International Airport in New York and of Patterson Air Force Base in Ohio.

Government agencies previously said they had “not identified anything anomalous”. They agreed with Biden that many drones that had been sighted were lawfully flown by hobbyists and law enforcement – adding that people were also spotting “manned fixed-wing aircraft, helicopters, and stars mistakenly reported as drones”.

But questions from the public remain. Earlier in the week, New Jersey man Noel Thomas described to the BBC his experience of spotting a mystery object in the sky. He said it was the size of a school bus, rectangular with blinking lights, and “definitely something I’ve never seen”.

A police officer in the same state said: “We’re just looking for some sound, reasonable answers so that people could go about their life and not live in this hysteria that we have going.”

As the mystery persists, state governments are calling for more power to deal with the small, uncrewed aircraft being spotted in the skies. Earlier this week, New York Governor Kathy Hochul said officials were sending her a drone detection system.

Among those who have voiced their suspicions are President-elect Donald Trump, who has said the government “knows what it happening”, but “for some reason they don’t want to comment”. However, he said he “can’t imagine it’s the enemy”.

The Pentagon earlier denied the suggestion of one New Jersey lawmaker that the possible drones came specifically from an Iranian “mothership”, while an FBI official said there may have been “a slight overreaction” on the topic.