US: Flying objects posed threat to commercial flights

The White House has defended its decision to shoot down mysterious flying objects over US airspace, saying they posed a threat to commercial flights.

John Kirby, from the White House National Security Council was addressing a press conference on Monday evening, as US officials face more pressure to explain more about a series of objects shot out of the sky.

An object downed on Sunday over Michigan was the fourth this month, with the first being a suspected spy balloon from China. It is still not clear what the three most recent objects to be shot down over North America were.

The White House has said they posed a threat to commercial flights, and were downed out of caution.

Earlier on Monday, China said the US has been flying balloons in its airspace over the last year. Kirby denied the claims.

“We are not flying surveillance balloons over China. I'm not aware of any other craft we're flying into Chinese airspace," he said.

Kirby denied the interceptions were due to political pressure following the incursion by the Chinese spy balloon. He said it was done because it was in the "best interests" of the American people - leaving open the door to speculation they were surveillance balloons.

He also said it was important to draw a distinction between the spy balloon allegedly operated by China taken down nearly two weeks ago and the three objects destroyed over the weekend.

Kirby added the Chinese balloon was at more than 60,000ft (18,000m), well above commercial aviation altitude - but the three others were at a height much more dangerous to normal commercial planes flying of between 20,000 and 40,0000ft.

He said the Chinese balloon was clearly being controlled and manoeuvred, while the other three objects did not have propulsion systems and were moving with the wind in a less predictable way.

Kirby also claimed the first balloon was likely being used to monitoring sensitive military sites. Asked if it was strange no one had claimed the three objects, Kirby said: "We're sort of in in uncharted territory here, no pun intended, we don't know."

Kirby said they are still working to get all of the Chinese spy balloon out of the water.

Some, not all of the payload that sank to the bottom of the Atlantic has been recovered.