When did China first know its balloon was in US airspace?

China suggested on Monday that it first knew one of its balloons had entered American airspace after it was notified by the United States.

Asked when Beijing found out the balloon was in US airspace, Chinese foreign ministry spokeswoman Mao Ning said the country started its assessment after the US told it about the incident.

“China is a responsible country. After the United States notified China, we immediately checked and gave feedback, and clearly requested the United States to act calmly, professionally, and handle it in a restrained manner,” Mao said.