On Friday, Canada’s national defense confirmed a potential second incident involving a suspected spy balloon and stated that officials are monitoring it.

“A high-altitude surveillance balloon was detected, and its movements are being actively tracked by [North American Aerospace Defense Command] NORAD,” the national defense said in a statement.

“Canadians are safe and Canada is taking steps to ensure the security of its airspace, including the monitoring of a potential second incident,” the statement added.

Officials from NORAD, the Canadian Armed Forces, the Department of National Defence, and other partners have been assessing the situation and working in close coordination, it said.

The national defence command said that the Canadian intelligence agencies are working with American partners and “continue to take all necessary measures to safeguard Canada’s sensitive information from foreign intelligence threats”.

“We remain in frequent contact with our American allies as the situation develops,” the national defence said.

This alert from Canadian defence officials comes just hours after the US military said it is tracking a suspected Chinese high-altitude spy balloon as it makes its way over the northern United States.

Pentagon spokesperson brigadier general Patrick Ryder said the US has so far decided against shooting down the surveillance balloon.

“The balloon is currently travelling at an altitude well above commercial air traffic and does not present a military or physical threat to people on the ground,” Mr Ryder said.

A senior defense official told Pentagon reporters that the US has “very high confidence” it is a Chinese high-altitude balloon and it was flying over sensitive sites to collect information.

The balloon was spotted over Montana, among of the places, where one of the US’s three nuclear missile silo fields at Malmstrom Air Force Base. The official spoke on condition of anonymity to discuss sensitive information.

The suspected spy balloon was seen over Billings, Montana, on Wednesday. It was about the size of three buses. It entered the US after flying in over the Aleutian Islands and making its way through Canada.