“Canadian and American aircraft were sent up, and an American F-22 successfully fired at the object,” he writes.
Trudeau ordered the shooting down after speaking with US President Joe Biden.
“Canadian forces will now retrieve and analyze the wreckage for the object,” writes Trudeau.
The North American air defense command Norad announced on Saturday evening, Swedish time, that an “airborne object at high altitude” was detected above northern Canada.
The object is the third known to have invaded North American airspace in the past two weeks. Last Friday, an unidentified object the size of a small car was sunk over Alaska, and last weekend a suspected Chinese spy balloon was destroyed as it passed over the United States.
In the past week, the US has accused China of using a global fleet of balloons to spy on countries around the world.
China initially denied the allegations about the balloon over the US but later claimed it was a civilian craft collecting data for research purposes.