It was the fourth flying object shot down over North America by the military in eight days.
United States fighter jets have shot down an “unidentified object” flying near the Canadian border in the Midwest, the Pentagon said, the latest incident since a suspected Chinese surveillance balloon put North American security forces on high alert.
The object was flying at 6,100 metres (20,000ft), and while it was not a military threat, it could have potentially interfered with domestic air traffic, Pentagon spokesperson Patrick Ryder said in a statement.
It was shot down at 2:42pm local time (19:42 GMT) over Lake Huron on the US-Canada border, the statement said.
It was the fourth flying object shot down over North America by the military in eight days.
US authorities have made clear that the country constantly monitors the skies for unknown radar blips, and it is not unusual to shut down airspace as a precaution while they evaluate the situation. But the more assertive response of recent days is raising questions about whether such force is warranted.
The flurry of defence activity began in late January when a white balloon appeared over the US and hovered over the country for days. The US said it was a suspected Chinese surveillance balloon and fighter jets eventually brought it down off the coast of South Carolina on February 4.
The latest object appeared to be octagonal in structure, with strings hanging from it but no discernible payload, an official told reporters.
It had been detected over Montana near sensitive military sites, prompting the closure of US airspace, the Pentagon said.
“We need the facts about where they are originating from, what their purpose is, and why their frequency is increasing,” said US legislator Debbie Dingell, one of several Michigan lawmakers who welcomed the move to shoot the craft down.
The latest object was first detected on Saturday evening over Montana but was initially thought to be an anomaly. Radar picked it up again on Sunday hovering over the Upper Peninsula of Michigan and moving over Lake Huron, according to US officials, who had knowledge of the incident and spoke to The Associated Press news agency on condition of anonymity to discuss the sensitive operations.
US and Canadian authorities had restricted some airspace over the lake earlier in the day as fighters were scrambled to intercept and try to identify the object.
Meanwhile, US officials are still trying to precisely identify two other objects shot down by F-22 fighter jets and were working to determine whether China was responsible amid concerns in Washington about what it believes is a large-scale aerial surveillance programme orchestrated by Beijing.
Canadian authorities are working to find the wreckage of the object shot down on Saturday over the Yukon, a sparsely populated region in the country’s far northwest.
“Recovery teams are on the ground, looking to find and analyse the object,” Prime Minister Justin Trudeau told reporters on Sunday.
“The security of citizens is our top priority and that’s why I made the decision to have that unidentified object shot down,” he said, adding that it had posed a danger to civilian aircraft.
The three latest flying objects were much smaller in size, different in appearance, and flew at lower altitudes than the suspected spy balloon.
China denies the first balloon was being used for surveillance and says it was a civilian weather monitoring station. It has condemned the US for shooting it down.