Canadian investigators are hunting for the wreckage of the mysterious flying object shot down by a U.S. fighter jet over Yukon territory, Prime Minister Justin Trudeau said Sunday, as the U.S. Senate's top lawmaker said that it — and another flying object shot down off the coast of Alaska — both appeared to be balloons.

"Recovery teams are on the ground, looking to find and analyze the object," Trudeau told reporters. He gave no hint as to what it was but said it "represented a reasonable threat to the security of civilian flight."

"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.