The US Civil Aviation Authority announced today, Sunday, that the airspace over Lake Michigan in the northern United States was closed for "national defense" reasons, after 3 flying objects, one of which Washington described as a Chinese spy balloon, were shot down over the United States and Canada within a week.

The authority later confirmed the reopening of the airspace over the lake, and said - in a statement - "The Federal Civil Aviation Authority briefly closed part of the airspace over Lake Michigan, to support the operations of the Department of Defense. The airspace has reopened."

Chuck Schumer, the leader of the Democratic majority in the US Senate - said - in an interview with the "ABC" television station - that US national security officials believe that the flying objects that were shot down over America and Canada were balloons.

"You can be assured that if there are any American interests in which people are at risk, they will take the appropriate action," Schumer added, adding that the two objects that were dropped on Friday and yesterday Saturday were smaller than the first balloon that roamed US airspace and was shot down over South Carolina last Saturday.

In turn, Canadian Prime Minister Justin Trudeau said - today, Sunday - that the teams are searching for the cylindrical object that was dropped by an American fighter over the Yukon Province in the far northwest of Canada on his orders a day ago, so that the teams can analyze it and learn more about its purposes.

"Research teams are working on the ground, looking forward to finding and analyzing the object," Trudeau told a news conference in Ottawa before leaving for a previously planned fund-raising event in the Yukon.

And he added, "There are many things we need to know, and that is why the analysis of this body is so important."

It is noteworthy that the US government had accused China of using the balloon, which was shot down a few days ago, for the purposes of "espionage on US military facilities", while Beijing said that it was a civilian research balloon that deviated from its course.

The US State Department also accused China of running a large-scale international surveillance program, targeting more than 40 countries on five continents with a fleet of spying balloons, allegations rejected by Beijing, accusing the US government of waging an "information war" on it.