White House Press Secretary Karine Jean-Pierre said in a press briefing acknowledged the questions on the nature of the UFOs downed in the past week.

In the past four days, the US fighter planes have shot down three UFOs over North America. The first was shot down by a US F-22 fighter over Alaska. The second was shot down in a joint US-Canada operation in North-western Canada's Yukon region by a US F-22 fighter on Saturday. The third was shot down over Luke Huron in America's Michigan state by a US F-16 on Sunday.?

Karine said, "There is no indication of aliens or terrestrial activity with these recent takedowns. Wanted to make sure that the American people knew that, all of you knew that and it was important for us to say that from here because we've been hearing a lot about it. I know there have been questions and concerns about this, but there is no, again, no indication of aliens or extraterrestrial activity with these recent takedowns."

Though the White House has said there is no indication yet on the alien or extra-terrestrial origin of the downed UFOs, there is no confirmation yet of their origin or nature. There are scarce details about their appearance and pilots that observed these UFOs reported strange behaviour.?

The possibility of the downed UFOs having alien-origin was ignited by a comment by US Northern Command and NORAD Commander General Glen VanHerck's in which he said he would not rule out extraterrestrial —alien— origin of these UFOs.

"I'll let the intel community and the counterintelligence community figure that out. I haven't ruled out anything. At this point we continue to assess every threat or potential threat, unknown, that approaches North America with an attempt to identify it," said VanHerck when asked about a possible alien-origin of these UFOs, as per Reuters.?

As for the reasoning behind the shoot-downs, the White House said the objects were flying in the civilian air traffic zone and this posed a threat. The White House also said their assessment rules out any immediate threat to anyone on the ground from the three downed UFOs.

White House national security spokesman John Kirby said were the three UFOs were travelling at such a low altitude as to pose a risk to civilian air traffic.

"First, there was a very real potential risk to civilian air traffic. ?The one shot down on Saturday — I’m sorry, yesterday — was about 20,000 feet. ?And the two shot down Friday and Saturday were at about 40,000 feet. And as you know, transcontinental air traffic is roughly around 30,000 feet. ?It depends, of course, on weather...The second purpose — and I talked about this earlier, too — was even though we had no indications that any of these three objects were surveilling, we couldn’t rule that out," said Kirby when asked why the UFOs were shot down if there was no immediate threat.?

Kirby also said the three UFOs that have been shot down are a separate episode from the Chinese spy balloon and should not be connected as of now.

"I think we need to separate the Chinese spy balloon. ?We knew what it was. ?We knew where it was going. ?We knew what it was trying to do...So let’s separate that from these other three," said Kirby, listing the unknowns about the UFOs, consisting their nature, origin, or purpose, all of which were known about the Chinese aircraft downed earlier this month off the American coast.

(With PTI, AP inputs)