Mysterious drone sightings over various US states do not pose a risk to public or national security, according to federal authorities.

There have been numerous reports of drone flights over New Jersey since mid-November, while others have been spotted more recently over Ohio, Virginia, Massachusetts and New York.

Some of the New Jersey sightings occurred near the Picatinny Arsenal, a military research and manufacturing facility, and over President-elect Donald Trump’s golf course in Bedminster.

One of the largest US air basesWright-Patterson Air Force Base near Dayton, Ohio, was closed for about four hours late Friday evening and into early Saturday morning, a base spokesman said.

Boston police arrested two men over the weekend accused of flying drones “dangerously close” to the city’s Logan Airport.

The sightings were followed by unmanned aerial vehicles spotted over and near four air bases used by the US Air Force (USAF) in the United Kingdom.

The British Ministry of Defense said at the time that it supported the USAF’s response to the sightings.

What did federal authorities say?

The Department of Homeland Security, the Federal Aviation Administration, the Defense Department and the FBI addressed the drone activity in a joint statement on Monday, saying they had received more than 5,000 reported sightings in recent weeks, 100 of which required further review.

But after reviewing the data, authorities said they “did not find anything unusual and do not assess the activity to date as a risk to national security or public safety.”

“We believe the sightings to date include a combination of legal commercial drones, hobby drones and law enforcement drones, as well as manned fixed-wing aircraft, helicopters and stars that have been falsely reported as drones,” authorities said.

“However, we are aware of the concerns of many communities. We continue to support state and local authorities with advanced detection technology and support law enforcement.”

The joint statement also said that more than one million drones are legally registered with the Federal Aviation Administration.

“Something strange is happening”

Attention to the sightings increased last week after New Jersey Gov. Phil Murphy, New York Gov. Kathy Hochul and some members of Congress demanded more information from federal officials after conspiracy theories emerged and public concern grew.

Andy Kim, Senator from New Jersey He also shared videos on social media of what he called several unidentified drones.

He said some of the unidentified objects appeared to move in “small groups of 2 to 4,” but they often saw “5 to 7 lights” at once.

The activity even prompted a comment from Mr. Trumpwho called on authorities to provide more information and said at a news conference that he planned to cancel a trip to his golf club in Bedminster.

“Something strange is happening,” he said. “For some reason they don’t want to tell people.”

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Conspiracy theories led to the creation of the Facebook page “New Jersey Mystery Drones – Let’s Solve It” – where people post their photos and videos of sightings.

It currently has around 79,000 members, up from 44,000 last week.

NBC News, Sky News’ U.S. affiliate network, reported that the House Intelligence Committee is scheduled to be briefed on the latest sightings on Tuesday afternoon.