A mystery flying object remains over Montana as fighter jets wait to "get eyes on it" after the search was called off until later today.
US and Canadian aircraft were quickly scrambled on Saturday night to Havre, which is 30 miles south of the Canadian border, forcing the airspace shut for 50 minutes.
Fighter jets were unable to find the mystery object, according to the The North American Aerospace Defense Command, who "did not identify any object to correlate to the radar hits."
They said they will continue to monitor the situation following three incidents this week - two Chinese spy balloons have been shot down over the US and a third object over Canada.
Montana congressman Matt Rosendale was at a dinner in Columbus, Montana when security officials called to brief him on the situation.
He told Fox News: "I'm at an event, a Lincoln Reagan dinner in Columbus, Montana right now.
"'And DOD called me as I have been sitting here and started giving me briefings to tell me what was going on.
"I clarified with them that this is actually the fourth balloon, OK."
Justin Trudeau, the Canadian Prime Minister, revealed just hours before on Saturday an "an unidentified object that violated Canadian airspace had been shot down by U.S. F-22s in Yukon by US and Canadian forces.
Mr Trudeau spoke with US President Joe Biden, who also ordered the object to be shot down.
Canadian and US jets operating as part of NORAD, the North American Aerospace Defense Command, were scrambled and it was a US jet that shot down the object.
It had been flying at around 40,000ft and was said to be "a small cylindrical object."
A recovery operation was underway involving the Canadian Armed Forces and the Royal Canadian Mounted Police.
Mr Rosendale added: "The first we shot down over the Atlantic. One was shot down before it entered into Alaska's airspace.
"A third was shot down, Trudeau ordered over Canada. So now we're talking about a fourth incident."
He continued: "DOD told me that they are going to be tracking the object - they can't even say exactly what it is - they are going to track the object until it gets light again.
"They don't have the ability to put any more eyes on it with aircraft until it's light again.
"And then tomorrow morning we'll be dealing with it."
NORAD confirmed a "radar anomaly" was seen, but jets "did not identify any object to correlate to the radar hits."
They said in statement: "'NORAD will continue to monitor the situation."
The governor of Montana Greg Gianforte revealed he had been brief at the White House on the mysterious object.
He tweeted: "'I received a briefing tonight at the White House about an object in Montana airspace.
"I will continue to receive regular updates.
"With questions about the Chinese spy balloon still unanswered, the Biden administration must be fully forthcoming with Montanans and all Americans."
F-22 fighter jets have now taken out three objects in the airspace above the US and Canada over seven days.
Mr Biden was forced to order a fighter jet to shoot down an unidentified "high-altitude object" off Alaska on Friday.
The object was flying at 40,000ft over the coast of Alaska and had reached speeds of 40mph.
It was travelling towards the North Pole before being shot down.
The White House said the object was "the size of a small car" and posed a "reasonable threat" to commercial flights.
Meanwhile, the first Chinese spy balloon was spotted floating over US waters was shot down last Saturday after John Kirby, White House National Security Council spokesman, said it posed a "reasonable threat" to the safety of civilian flights.
However, China has rejected claims the objects were part of a spying mission and said they were civilian meteorological balloons that had blown off course.
