For the third day in a row and fourth time in just nine days, the United States has shot down an unidentified high-flying object.

Today, it happened over Lake Huron, between Michigan and Canada.

A senior administration official telling NBC News the unmanned object was detected over Montana, Wisconsin, and Michigan.

And at the direction of President Biden, it was shot down.

It was just yesterday afternoon that a US fighter jet took down another flying object over northern Canada,

and the search is still on for what remains of whatever was shot down over Alaska on Friday.

This string of events raising so many questions:

Are these all spy balloons similar to the Chinese balloon shot down off South Carolina last weekend?

Are these a new threat?

Or is the US just tracking them more closely now?

Some lawmakers on both sides of the aisle demanding more information from the Biden administration.

We have two reports tonight; let's start with Monica Alba at the White House.

Tonight, the US military shooting down another high-altitude, unidentified flying object.

This time, over Lake Huron.

The Pentagon saying in a statement, the object "flew in proximity to sensitive DOD sites" and assessed it was "a safety flight hazard and a threat due to its potential surveillance capabilities".

The FAA issuing a temporary flight restriction over nearby Lake Michigan earlier Sunday afternoon, citing Department of Defense activities,

coming just hours after airspace was restricted over Montana Saturday night for the same reason, initially assessed as a "radar anomaly",

Then, I think, it got dark last night, so they couldn't fully check it out.

as new details emerge about the flying object shot down by the US over northern Canada Saturday.

An F-22 taking out a small cylindrical objected first spotted in American airspace Friday.

A carefully-coordinated mission between the two countries.

This was the first time that a NORAD operation has downed an aerial object.

The object was flying at an altitude of approximately 40,000 feet, had unlawfully entered Canadian airspace, and posed a reasonable threat to the safety of civilian flight.

We're always going to detect, and we're always going to defend our airspace.

Saturday's military operation came just a day after the President authorized the US to take aim at another unidentified object off the coast of Alaska,

where those tasked with recovering debris are battling severe windchill and limited daylight,

as a bipartisan call for transparency from the White House and Pentagon grows louder.

In the absence of information, people's anxiety leads them into potentially destructive areas.

So, I do hope that, very soon, the administration has a lot more information for all of us on what's going on.

I would prefer them to be trigger-happy than to be permissive.

This shows some of the problems and gaps that we have; we need to fill those as soon as possible.

'Cause we certainly, now, ascertain there is a threat.

And Monica joins us now; what else do we know about the object shot down today?

Well, Kate, President Biden authorized an F-16 fighter jet to take it out this afternoon,

and a US official tells me it appeared to be octagon-shaped, with strings hanging off of it. Kate.

Monica Alba, thank you.

Let's get right to our Pentagon correspondent Courtney Kube; she's been following all of this from the beginning.

Courtney, what could these objects possibly be?

So, we only know about the first one, that that was a high-altitude Chinese surveillance balloon.

The other three are smaller; it's not clear who owns them.

And we don't even really know what they were doing; whether it was surveillance or something else.

We do know that the US would take a couple (of) things into account when deciding whether to shoot them down.

One is whether they pose a threat to civilian or military aviation.

The next is, do they pose a threat to people on the ground?

And then, finally, do they pose some sort of a general national threat?

Those would've been taken into consideration when deciding to take it down.

And the biggest question everyone has:

Is there some kind of increase in the number of flying objects right now, or were they always there and the military is just finding them?

That's also not clear.

We know that the US military, now, is looking at a wider range of radar data, so, they may just be seeing more of these things than they have in the past.

But it's not clear whether now, recently, they're moving more into US airspace and that's causing the concern,

or whether this is just an entirely new phenomenon just in the recent days.

Courtney Kube, thank you so much.

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