US secretary of state Antony J. Blinken on Friday postponed a trip to Beijing after a Chinese high-altitude balloon, described as an “intelligence-gathering” airship by the Pentagon and a stray civilian device by China, was detected floating over the US this week.

The postponement was confirmed by the state department officials, citing the balloon and speaking on the condition of anonymity to discuss sensitive issues.

Blinken and a deputy spoke with the Chinese embassy on Wednesday night, and on Friday morning Blinken told China’s top foreign policy official, Wang Yi, that the balloon’s course was a violation of sovereignty and “unacceptable”, according to the state department official. There is no new date for Blinken’s trip to Beijing, the official added.

Beijing had sought to defuse tensions with Washington on Friday over the balloon, expressing its regret over the incident, and saying the balloon was for civilian research and had “deviated far from its planned course”.

The explanation from the Chinese foreign ministry came after Pentagon officials said on Thursday that they had detected a balloon, “most certainly launched by the People’s Republic of China”, over Montana, which is home to about 150 intercontinental ballistic missile silos.

After initially telling a news conference that it had to check on the claims about the balloon, the ministry said late on Friday in Beijing that the balloon’s course was an innocent mistake.

“The airship is from China. It is a civilian airship used for research, mainly meteorological, purposes,” an unidentified spokesperson for the ministry said in a statement on its website.

“Affected by the Westerlies and with limited self-steering capability, the airship deviated far from its planned course. The Chinese side regrets the unintended entry of the airship into US airspace due to force majeure.”

“Force majeure” refers to a violation caused by forces beyond a party’s control.

Neither side has suggested that Beijing communicated with Washington about the balloon before the controversy broke on Thursday. But China said in its statement on Friday that it would now talk with US officials about how to “properly handle this unexpected situation”.

While the Pentagon played down the potential value of the balloon for acquiring intelligence, the initial public reaction by Biden administration officials had underscored how brittle and delicate relations with Beijing have become, even over one balloon.

The defence secretary, Lloyd J. Austin III, held ameeting about the balloon with senior US defence officials while he was in the Philippines, and President Biden“ was briefed and asked for military options”, a Pentagon official told reporters.

China appeared eager to avoid letting the balloon become a festering irritant during Blinken’s planned two-day visit to Beijing, which had been scheduled to begin on Sunday.

Speaking before China’s statement was issued, Drew Thompson, a former Pentagon official who is now a visiting senior research fellow at the Lee Kuan Yew School of Public Policy at the National University of Singapore, said the timing of the balloon flight was at least maladroit.

China is also smarting over the US announcement on Thursday that it would expand its military presence in the Philippines.

New York Times News Service