The UK will conduct a security review after a series of objects in Western airspace were shot down by the US military, including a suspected Chinese spy balloon.
Defence Secretary Ben Wallace announced plans to assess the dangers posed the balloons on Sunday.
Mr Wallace said: "The UK and her allies will review what these airspace intrusions mean for our security.
"This development is another sign of how the global threat picture is changing for the worse."
It comes after US fighter jets shot down an "unidentified object" over Lake Huron on Sunday - the fourth object to enter US or Canadian airspace in just over a week.
Senator Jack Bergman said he'd been told by the Department of Defense on Sunday that the military had "decommissioned" another "object" over Lake Michigan-Huron.
In a tweet, he added: "I appreciate the decisive action by our fighter pilots.
"The American people deserve far more answers than we have."
Congresswoman Elissa Slotkin said: "We’re all interested in exactly what this object was and its purpose."
The Federal Aviation Administration issued a notice at 11am local time, confirming flights in the area had been restricted for unspecified reasons.
Two hours later, it said the airspace had been reopened.
On February 4, the US military downed a suspected Chinese spy balloon off the Carolina coast after it traversed sensitive military sites across North America.
Almost a week later on Friday, they shot down an unknown "car-sized" object flying in US airspace off the coast of Alaska.
Prime Minister Justin Trudeau said on Saturday that he ordered a US warplane to shoot down an unidentified object that was flying high over northern Canada.
On Sunday, a further unidentified object was shot down with a missile by US fighter jets over Lake Huron.
Spy balloons may have already been deployed by China across Britain's airspace, according to Tory Minister Richard Holden.
"It is possible," he told Sky News.
"It is also possible, and I would think likely, that there would be people from the Chinese government trying to act as a hostile state."
He added: "I think we have to be realistic about the threat these countries pose to the UK."
Asked how concerned ministers were about the US shooting down unidentified objects in recent days, Mr Holden said: "I think the Government is concerned about what's going on."
