A US fighter jet shot down an "object" flying over Alaska on Friday, in a new -- but much swifter -- repeat of the downing of a Chinese spy balloon last week that threw ties between the two countries into a new crisis.

The object -- that's what the US is calling it at this early stage of investigation -- was described by Defence officials as large as a car -- in contrast to the Chinese balloon which was the size of three passenger buses. But the officials acknowledged they had few other details -- nothing about its ownership, origin, or purpose.

"I can confirm that the Department of Defence was tracking a high-altitude object over Alaska airspace in the last 24 hours. The object was flying at an altitude of 40,000 feet and posed a reasonable threat to the safety of civilian flight," John Kirby, spokesperson of the US National Security Council said in a White House briefing.

He added: "Out of an abundance of caution and at the recommendation of the Pentagon, President Biden ordered the military to down the object. And they did, and it came inside our territorial waters. Those waters right now are frozen -- but inside territorial airspace and over territorial waters."

Pressed for more details, Kirby said, "We're calling this an 'object' because that's the best description we have right now. We do not know who owns it, whether it's a -- whether it's state-owned or -- or corporate-owned, or privately owned. We just don't know."

The US Department of Defence gave some more details at a separate briefing: the object was first noted on Thursday by the North American Aerospace Defence Command (NORAD). It was flying at an altitude of 40,000 feet and "posed a reasonable threat to the safety of civilian flight".

An F-22 fighter jet that took off from an airbase in Alaska brought down the object with an IM-9X missile.

But this flying object was not carrying any surveillance equipment -- compared to the massive payload the size of three passenger buses of the spy balloon -- and could not maneuver itself.

The Chinese spy balloon had entered the US also through Alaska and was allowed to drift across the breadth of the American landmass till it was safely out of water because it was shot down. After all, the US military feared danger to the civilian population down below from falling debris.

Republican Senators grilled Defence officials at a hearing on Thursday for, one, allowing the spy balloon to enter Alaska and, two, letting it fly across the state and into the American mainland.

"As an Alaskan, I am so angry, I want to use other words, but I'm not going to," Lisa Murkowski, a Republican Senator from Alaska, to Defence officials.

"It's like this administration doesn't think that Alaska is any part of the rest of the country here ... To get to the US, you've got to come through Alaska."

The detection and downing of the balloon ushered new tensions between the US and China just as they had seemed on the verge of better understanding and engagement -- compared to the Trump' years -- building on the first in-person summit between Presidents Joe Biden and Xi Jinping.

US Secretary of State Antony Blinken postponed his visit to Beijing just hours before take-off and Biden celebrated the shooting down of the balloon with a taunt directed at the Chinese President in his State of the Union speech, saying he had left Xi in an unenviable place, which no other world leader would want. (KB/IANS)