Pentagon chiefs have admitted they do not know the origins of the mysterious objects that have been brought down.
Fighter jets have been scrambled to bring down a balloon and three unidentified orbs over the past eight days.
It comes just a week after a Chinese spy balloon was shot down off the coast of South Carolina.
On Sunday, pilots downed a high-altitude “octagonal” orb after it was spotted flying at 20,000 feet over Lake Huron near Michigan, The Sun reported.
Defence officials brought down the object after it was deemed a risk to commercial aircraft.
General Glen VanHerck, the head of the US North American Aerospace Defense Command, has not ruled out any theory when it comes to the objects‘ potential origins.
He said: “I’ll let the intel community and counterintelligence community figure that out. I haven’t ruled out anything.
“At this point, we continue to assess every threat or potential threat, unknown, that approaches North America with an attempt to identify it.”
Brig. Gen. Pat Ryder, the Pentagon press secretary, revealed officials shot the object down as it was a flight hazard.
He told reporters: “We did not assess it to be a kinetic military threat to anything on the ground, but assess it was a safety flight hazard and a threat due to its potential surveillance capabilities.”
Footage shared online appeared to show the orb spinning before it was brought down.
On Saturday, an American aircraft shot down an unidentified object that was flying above Canada.
Canadian prime minister Justin Trudeau confirmed that the object had “violated” the country’s airspace before it was brought down.
Officials at the Federal Aviation Administration confirmed that the airways in Montana were briefly closed to support the operation.
According to a graphic released by the FAA, the airspace closed was near Havre, Montana, just under the Canada-US border.
A “radar anomaly” was detected, leading officials to send a fighter pilot to investigate, the North American Aerospace Defense Command confirmed.
And, an object that was zooming at 40,000 feet was brought down over Alaska on Friday.
An F-22 aircraft shot it down with a Sidewinder missile after it entered Alaskan airspace, with its remains scattering across the frozen sea.
According to Politico, pilots tasked with shooting down the object described it as “cylindrical.”
CNN reporter Natasha Bertrand revealed the fighter pilots that brought down the orb revealed they “were not able to identify what they saw”.
She told the outlet: “When the US first detected this object over Alaska on Thursday, they sent up F-35 jets to … see what was going on.
“And these pilots reported back very conflicting accounts.”
Bertrand said the pilots didn‘t know why the object was “interfering” with their aircraft’s sensors.
She added: “Then other pilots were saying that they did not see anything on the object that appeared able to propel it, that it seemed like there was no way that this was actually able to stay in the air.”
The mysterious object was compared to the size of a “small car”.
Alaska Governor Mike Dunleavy praised the military for “eliminating the potential threat before it was flying over our land”.
Earlier this month, a Chinese spy balloon was downed over the Atlantic Ocean after it travelled over American airspace for several days.
The saga sparked potential security fears.
Officials said the balloon had flown over areas in Montana containing sensitive air bases and nuclear missiles in underground silos.
Montana is home to the Malmstrom Air Force Base, which houses one of the three nuclear missile fields in the U.S. It is home to 150 intercontinental ballistic missiles (ICBM) silos.
The Chinese government claimed the balloon was “for weather research” and inadvertently crossed into US territory due to wind gusts.
But, president Biden‘s handling of the saga was criticised by leading Republicans.
Mike Turner, the House Intelligence Committee Chairman, told NBC News: “The president taking it down over the Atlantic is sort of like tackling the quarterback after the game is over. The satellite had completed its mission.
“This should never have been allowed to enter the United States, and it never should have been allowed to complete its mission.”
GOP politician Mike Gallagher claimed the incident made the U.S. look “weak” on the world stage.
He told Fox: “Letting a Chinese surveillance balloon lazily drift over America is like seeing a robber on your front porch and inviting him in, showing him where you keep your safe, where you keep your guns, where your children sleep at night, and then politely asking him to leave. It makes no sense.”
Texas Senator Ted Cruz told CBS News that the saga “telegraphed weakness” to President Xi.
This article originally appeared in The Sun and was reproduced with permission