The United States has shot down four mostly unidentified flying objects, including one in Canada, in just over a week.
Starting with the downing of a suspected Chinese spy balloon over the Atlantic Ocean earlier this month, the U.S. has since taken down another three smaller unidentified objects.
They include one off the coast of Alaska, another over central Yukon and one over Lake Huron.
Here is what we know about where these four objects were shot down:
FEB. 4
After spending a week crossing the U.S. and Canada, a suspected Chinese spy balloon finally made its way off the South Carolina coast on Feb. 4, where the U.S. shot it down over the Atlantic Ocean.
Military officials said bringing the balloon flying at an altitude of 60,000 feet down over land posed a risk to people on the ground. The balloon has been described as being the size of three school buses.
However, critics have questioned why action wasn't taken sooner.
China, meanwhile, has maintained that a meteorological surveillance balloon accidentally drifted off course and into the U.S.
FEB. 10
A U.S. fighter jet shot down an unidentified object off the northern coast of Alaska on Feb. 10.
The object flew at a lower altitude than the balloon at about 40,000 feet and was smaller, about the size of a small car.
White House National Security Council spokesman John Kirby said the object was downed because its altitude posed a "reasonable threat" to the safety of civilian flights, not because of any knowledge that it was engaged in surveillance.
Commercial airliners and private jets can fly as high as 45,000 feet, or 13,700 metres.
FEB. 11
As part of a North American Aerospace Defence Command (Norad) operation, Canadian and U.S. fighter jets were tasked on Feb. 11 with intercepting an unidentified object that had entered Canada's airspace.
A U.S. fighter jet eventually shot down the object over central Yukon.
Canadian Defence Minister Anita Anand described the object as "cylindrical" and also smaller than the suspected Chinese spy balloon.
Similar to the previous object, Anand said this one flew at approximately 40,000 feet in the air and posed a "reasonable threat" to the safety of "civilian flight."
FEB. 12
A U.S. fighter jet shot down another unidentified object over Lake Huron on Feb. 12, the fourth such downing in eight days.
The U.S. took down the object, which has been described as having an octagonal shape, as it flew at an altitude of 20,000 feet.
Both Canadian and U.S. aircraft were involved in the operation through Norad.
Map by Â鶹´«Ã½' Jasna Baric. With files from CTVNews.ca Writer Daniel Otis, The Canadian Press and The Associated Press.
