Chinese officials shared “regret” on Friday and claimed the balloon was conducting meteorological research and had been accidentally blown off course by winds.
A Pentagon official called the air balloon “a clear violation of US sovereignty” at a press briefing on Friday and and dismissed China’s claims that it is not a spy ship.
The Pentagon has resisted calls from Republican lawmakers to shoot the “intelligence gathering” airship down.
Since revealing it was flying at high altitude above Billings, Montana, on Wednesday, officials have given little away about its precise location.
Secretary of State Antony Blinken called off a planned trip to Beijing this weekend as the diplomatic stand-off intensified.
What we know about the airship’s flight path
A Pentagon official said during a briefing on Thursday that the balloon, which is roughly the size of three large buses, was first sighted over the Aleutian Islands earlier this week.
The archipelago of about 300 islands is located between Alaska and Russia and borders the northern edge of the Pacific Ocean and the Bering Sea.
The airship then travelled over northern Canada at an altitude well above commercial air traffic, officials said.
The balloon then headed south, and was sighted over the skies of Montana around the city of Billings.
Ashley McGowan, who lives in Reed Point, about 60 miles west of Billings, told CNN she saw a bright white dot in the sky on Wednesday.
Ms McGowan said she initially wondered if it might be a UFO, space junk or a comet.
She said there were US Air Force jets “flying everywhere” around the airship.
Billings is roughly 200 miles southeast of Malmstrom Air Force Base, where the US has 150 nuclear warheads across its 13,800-square-mile complex.
The Pentagon reportedly scrambled fighter jets, including F-22s, to potentially shoot down the balloon if ordered to by the White House.
However, the White House decided against the escalatory move over concerns that the debris could injure or kill residents on the ground.
At a press briefing at midday on Friday, Pentagon Press Secretary Brigadier General Pat Ryder said the balloon was currently over the centre of the continental United States.
Pressed for further details, he refused to say precisely where the ballon was.
“The public certainly has the ability to look up in the sky and see where the balloon is.”
He said it was travelling eastwards, and that the US was continuing to monitor its options.
The North American Aerospace Defence Command (NORAD) has so far been vague about the balloon’s trajectory.
In a statement on Thursday night, Brig Gen Ryder said the US Government “has detected and is tracking a high altitude surveillance balloon that is over the continental United States right now”.
It hasn’t provided an update on the balloon’s location since Thursday.
Meanwhile, Canada’s national defence department said it had also detected the balloon and was “monitoring a potential second incident”.
During Friday’s briefing, a Pentagon official said the airship had flown close to “a number of sensitive sites”.
The official said the US was taking steps to mitigate any foreign intelligence risk.