It was downed by Air Force and National Guard pilots on Sunday, Michigan Congresswoman Elissa Slotkin said.

"Great work by all who carried out this mission," she wrote on Twitter.

Washington has been on high alert since its military destroyed a suspected Chinese spy balloon on 4 February.

That balloon was tracked across the continental US before it was shot down off the coast of South Carolina. Officials recovered some of its debris from the ocean and said the balloon originated in China and was used for surveillance - but China denies it was used for spying.

Since then, American fighter jets have shot down three further high-altitude objects in as many days.

On Friday, President Joe Biden ordered an object to be shot down over Alaska. And on Saturday a similar object was shot down over the Yukon in north-west Canada.

Officials have not publicly identified the suspected origin of these objects. Both the US and Canada are working to recover the remnants, but the search in Alaska has been hampered by Arctic conditions.

"These objects did not closely resemble, and were much smaller than, the [4 February] balloon and we will not definitively characterise them until we can recover the debris," a White House National Security spokesperson said.

Little is known about the object that was shot down on Sunday, with officials yet to give any details about its size or appearance.

But earlier on Sunday, the top Democrat in Congress said intelligence officials believed the flying objects that were shot down on Friday and Saturday were surveillance balloons.

"They believe they were [balloons], yes," Senate Majority Leader Chuck Schumer told ABC News, adding that they were "much smaller" than the first one shot down off the South Carolina coast.

"The bottom line is, until a few months ago, we didn't know of these balloons," he said.

"We're going to probably be able to piece together this whole surveillance balloon and know exactly what's going on," Mr Schumer added.