US Secretary of State Antony Blinken has postponed a planned diplomatic trip to China after the discovery of a high-altitude Chinese balloon flying over sensitive sites in the western United States.
The abrupt decision comes despite China's claim that the balloon was a weather research satellite that had blown off course.
The US has described it as a surveillance satellite.
The decision came just hours before Mr Blinken had been due to depart Washington for Beijing and marked a new blow to already strained US-Chinese relations.
Officials said Mr Blinken and President Joe Biden determined it was best not to proceed with the trip at this time.
The Pentagon has been monitoring the suspected Chinese spy balloon that has been flying over the United States for a couple of days, according to US officials.
Fighter jets were mobilised and military leaders considered shooting down the balloon over Montana on Wednesday, but eventually advised President Joe Biden against it for fear debris could pose a safety threat, US officials said.
The United States took “custody” of the balloon when it entered US airspace and had observed it with piloted US military aircraft, an official who wished to remain anonymous told reporters.
On Friday, China claimed the balloon was actually for civilian meteorological and other scientific purposes as it voiced regret for it straying into US airspace.
In a statement, China’s foreign ministry: “The airship is from China and is civilian in nature, used for meteorological and other scientific research. Due to the influence of westerly winds and its limited control capability, the airship deviated from its intended course.
“China regrets that the airship strayed into the United States by mistake due to force majeure. China will continue to maintain communication with the US side to properly handle this accident.”
Chase Noak, a resident of Billings, Montana, who filmed the balloon on February 1, said he initially thought it was a star.
“But I thought that was kind of crazy because it was broad daylight and when I looked at it, it was just too big to be a star,” he told news agency Reuters.
The presence of the balloon comes just days ahead of a planned trip to Beijing by US Secretary of State Antony Blinken.
Separately, Canada’s defence ministry said it was monitoring a “potential second incident” after a “high-altitude surveillance balloon” was detected. It did not give further details, but added it was in frequent contact with the United States.
The news initially broke as CIA Director William Burns was speaking at an event at Washington’s Georgetown University, where he called China the “biggest geopolitical challenge” currently facing the US.
“The United States government has detected and is tracking a high-altitude surveillance balloon that is over the continental United States right now,” Pentagon spokesperson Brigadier General Patrick Ryder told reporters.
“The balloon is currently travelling at an altitude well above commercial air traffic and does not present a military or physical threat to people on the ground.”
The Chinese foreign ministry did not immediately respond to a request for comment made by news agency Reuters.
A Chinese spy balloon over the U.S. is alarming but not surprising
— Marco Rubio (@marcorubio) February 2, 2023
The level of espionage aimed at our country by Beijing has grown dramatically more intense & brazen over the last 5 years
US officials said they raised the matter with their Chinese counterparts through diplomatic channels. “We have communicated to them the seriousness with which we take this issue,” a US official said.
An official said the balloon’s current flight path would carry it over a number of sensitive sites, but they did not give details. Malmstrom Air Force Base in Montana is home to 150 intercontinental ballistic missile silos.
But the balloon was assessed to have “limited additive value from an intelligence collection perspective.”
US Senator Marco Rubio, the top Republican on the Senate intelligence committee, said the spy balloon was alarming but not surprising.
“The level of espionage aimed at our country by Beijing has grown dramatically more intense & brazen over the last 5 years,” Mr Rubio said on Twitter.
Mr Blinken is expected to travel to China next week for a visit agreed to in November by Mr Biden and Chinese President Xi Jinping. It was not clear how the discovery of the spy balloon might affect those plans.
Republican Senator Tom Cotton called for Mr Blinken to cancel his trip.
Relations between China and the United States have soured in recent years, particularly following then-US House Speaker Nancy Pelosi’s visit to Taiwan in August, which prompted dramatic Chinese military drills near the self-ruled island.
Since then, Washington and Beijing have sought to communicate more frequently and prevent ties from worsening.
Spy balloons have flown over the United States several times in recent years, but this balloon appeared to be lingering longer than in previous instances, one US official said.
Craig Singleton, a China expert of the Foundation for Defence of Democracies, said such balloons had been widely used by the United States and Soviet Union during the Cold War and are a low-cost intelligence gathering method.