The federal defence minister says Canada "unequivocally supports" the United States government's decision to shoot down a high-altitude surveillance balloon that was suspected of spying for China, noting the balloon violated Canadian airspace.

Fighter jets downed the balloon off the Carolina coast on Saturday afternoon after it had travelled over sensitive military sites across North America.

Anita Anand issued a statement hours later saying she and Prime Minister Justin Trudeau were briefed on the operation by the national security and intelligence advisor and the chief of the defence staff beginning on Friday night and continuing Saturday.

She said Canada has been closely engaged with its American counterparts on the decision and went on to thank the U.S. for its close collaboration.

A Pentagon official described the object as a manoeuverable surveillance balloon flying at an altitude of about 18,288 metres, with a "payload" or basket underneath.

On Friday, Anand's office declined to comment on whether the balloon flew over Canadian airspace, but her Saturday statement says it "violated U.S. and Canadian airspace and international law."

“Officials in the national security community have been working bi-nationally and Canada has been closely engaged with its U.S. counterparts on the decision and unequivocally supports the actions taken," Anand said in the statement. 

U.S. President Joe Biden said on Saturday he ordered U.S. officials to shoot down the balloon earlier this week and that national security leaders decided the best time for the operation was when it moved over water.

The Chinese Foreign Ministry has said the balloon was a civilian airship used mainly for meteorological research that "deviated far from its planned course" because of winds.

Anand noted Saturday that Norad, the North American Aerospace Defense Command, had been "tracking and analyzing the trajectory and actions" of the balloon.

"The co-operation between Canada and the United States through Norad ensures the security and defense of North American air sovereignty, and we thank its members for having the watch," she said.

Pentagon officials have said one of the places the balloon was spotted was over the state of Montana, which is home to one of America's three nuclear missile silo fields at Malmstrom Air Force Base.

U.S. Defense Secretary Lloyd Austin said in a statement the decision to shoot down the balloon "safely" over U.S. waters was "taken in coordination, and with the full support, of the Canadian government."

"And we thank Canada for its contribution to tracking and analysis of the balloon through Norad as it transited North America," Austin said in the statement.

Global Affairs Canada said Friday that officials summoned Chinese Ambassador Cong Peiwu to express disapproval over the balloon. 

U.S. officials also announced Secretary of State Antony Blinken was postponing a planned high-stakes weekend diplomatic trip to China.

This report by The Canadian Press was first published Feb. 4, 2023.