US authorities have been unable to provide definitive answers, saying only that the objects are not believed to pose a danger to the public or national security.

On Thursday, White House national security spokesman John Kirby told reporters that available images suggested that many of the reported drone sightings were actually manned aircraft.

But some lawmakers have criticised the government’s handling of the drones and the lack of information available to the public.

Here’s what we know.

Dozens of drone sightings have been reported over New Jersey since 18 November, according to local authorities.

The drones were initially spotted near the Raritan river, a waterway which feeds into the Round Valley Reservoir – the largest in New Jersey, the Associated Press reported.

The sightings soon spread to other parts of the state, including New Jersey’s coast.

Some of the flights were spotted near Picatinny Arsenal – a sensitive military research facility – as well as near President-elect Donald Trump’s golf course in the town of Bedminster, New Jersey.

In nearby New York City, several drones were reported flying over the Bronx on 12 December, a police official told CBS News.

Officers who responded to the incident saw the drones flying overhead, but they disappeared soon afterwards.

Drones have also been reported in other parts of the state, according to New York State Police.

Police in Connecticut have also confirmed that “suspicious drone activity” has taken place in various parts of the state. A drone detection system has been deployed around the towns of Groton and New London.

In Maryland, former Republican Governor Larry Hogan claimed he saw what appeared to be “dozens” of drones over his residence in Davidsonville, about 25 miles (40km) from Washington DC.

“Like many who have observed these drones, I do not know if this increasing activity over our skies is a threat to public safety or national security,” he wrote on X. “But the public is growing increasingly concerned and frustrated with the complete lack of transparency and the dismissive attitude of the federal government.”

In late November, the United States Air Force also confirmed that unidentified drones were spotted over three US airbases in the UK: RAF Lakenheath and RAF Mildenhall in Suffolk and RAF Feltwell in Norfolk.

UK defence sources told the BBC that suspicion had fallen on a “state actor” being responsible for the incursions.

In October, the Wall Street Journal also reported that mysterious drones were seen for 17 days near US military facilities in Virginia.

In a call with reporters, officials from several US agencies attempted to assure people that the drones were not the work of a foreign actor or a national security threat.

“I think there has been a slight overreaction” an official from the FBI said.

While downplaying public concern, the authorities were keen to reiterate that investigations into the drone sightings were still underway.

“We certainly understand why people are concerned. That’s one of the reasons we’re devoting significant resources,” the Department of Homeland Security (DHS) said.

“At the same time, it’s important to understand that we don’t have any current evidence that there’s a threat to public safety” the DHS added.

Both federal and state authorities have said that they do not believe the drones are dangerous or pose a threat to US national security.

Following a briefing with the Department of Homeland Security on 11 December, New Jersey assemblywoman Dawn Fantasia said the drones appear to avoid detection by traditional methods such as helicopter and radio.

Fantasia said the drones are up to 6ft (1.8m) in diameter, travel with lights turned off and “operate in a co-ordinated manner”.

Her comments stand in stark contrast to the White House, which has suggested that these are “manned aircraft”.

The FBI and the Department of Homeland Security also said that the majority of sightings appear to be lawful, manned flights.

None have been reported in restricted airspace, the statement added.

The Federal Aviation Administration (FAA) released a statement on Friday saying more and more people are using drones, meaning more people are noticing them in the sky.

It added that while drones can be flown in most locations below 400ft (121m), drones can’t be flown within controlled airspace around an airport without FAA authorisation; over designated, national security-sensitive facilities; in certain military bases, infrastructure and national landmarks; and in airspace covered by temporary flight restrictions.

If the objects are confirmed to be drones – which at this point is unconfirmed – it is unclear who might be operating them.

Citing anonymous “high sources”, New Jersey Republican representative Jeff Van Drew said that they were coming from an Iranian “mothership” in the Atlantic.

The Pentagon swiftly dismissed the comment, saying “there is no truth to that”.

“There is no Iranian ship off the coast of the United States, and there’s no so-called mothership launching drones towards the United States,” deputy spokesperson Sabrina Singh told reporters.

Another lawmaker, Illinois Democrat Raja Krishnamoorthi – who is on a congressional committee that looks at China’s Communist Party – told media outlet NewsNation that there is a “non-trivial” chance that China could be involved.

“It’s definitely a possibility and the likelihood that they can then access data that is collected by these drones is very high,” he said.

The Pentagon and White House have both insisted that there is no foreign origin for the objects.

Van Drew and other lawmakers have pushed back on those denials.

“Here’s the deal: they don’t know what it is. They don’t know what it’s about,” Van Drew told Fox News. “They have no idea where it comes from, but they know what it’s not about? That’s nonsense.”

In a separate incident across the country, a northern California man was charged on 11 December with flying a drone over and taking pictures of Vandenberg Space Force Base, located near Santa Barbara.

The incident is alleged to have taken place on 30 November, according to prosecutors.The man, 39-year-old Chinese national Yinpiao Zhou was arrested just before he boarded a flight to China. He appeared in court on Tuesday and no plea was was taken.

There has been no suggestion that the incident is related to the spate of reported drone sightings on the east coast.

Several lawmakers have suggested that the drones should be shot down and analysed to determine their origin and intentions.

Among them is President-elect Donald Trump, who took to his Truth Social media platform to suggest that drones couldn’t be flying without the government’s knowledge.

“Let the public know, and now,” he wrote. “Otherwise, shoot them down”.The US Federal Aviation Administration has also established temporary flight restrictions prohibiting drone flights over Bedminster and Picatinny.

In a statement, the FAA also warned that drone operators who conduct unsafe or dangerous operations could face fines of up to $75,000 (£59,000) and have their drone pilot certificates revoked.

In a letter to US President Joe Biden published on 13 December, New Jersey Governor Phil Murphy urged federal agencies to “work together” to solve the mystery, as well as push Congress to extend counter-drone capabilities to local law enforcement.

Some residents have suggested they may take action against the drones themselves – something authorities have strongly warned against doing, as it is illegal.

“A good shotgun will fix that problem,” a man commented on a video of a drone on social media.