Pentagon Says It Detected a Chinese Spy Balloon Hovering Over Montana

WASHINGTON — The United States has detected what it says is a Chinese surveillance balloon that has been hovering over the northwestern United States, the Pentagon said on Thursday, a discovery that comes days before Secretary of State Antony J. Blinken’s visit to Beijing.

The Pentagon has chosen, for now, not to shoot down the balloon after a recommendation from senior defense officials that doing so would risk debris hitting people on the ground, according to a senior defense official who was not authorized to speak publicly.

The decision to publicize the discovery appears to put China on notice ahead of Mr. Blinken’s Beijing visit — the first by an American secretary of state in six years — during which he is expected to meet with President Xi Jinping. The sudden appearance of the balloon is bound to raise already escalating tensions between the two powers.

The official said that while it was not the first time China had sent spy balloons to the United States, this one has appeared to remain over the country for longer. Still, a senior administration official who spoke on condition of anonymity said the balloon did not pose a military or physical threat and added that it had limited value in collecting intelligence. Another defense official said the Pentagon did not think that the balloon added much value over what China could glean through satellite imagery.

Pentagon officials said the balloon had traveled from China to the Aleutian Islands of Alaska, and through northwest Canada over the past few days before arriving somewhere over Montana, where it was hovering on Wednesday.

It was unclear what China was looking for in Montana, but the state is home to the 341st Missile Wing at Malmstrom Air Force Base, one of three American Air Force bases that operate and maintain intercontinental ballistic missiles.

Brig. Gen. Patrick S. Ryder, the Pentagon press secretary, told reporters that the balloon was traveling “well above commercial air traffic,” adding that “once the balloon was detected, the U.S. government acted immediately to protect against the collection of sensitive information.” He did not specify what those measures were.

The Pentagon sent F-22 fighter jets to track the balloon Wednesday, leading to flights being temporarily grounded at the Billings airport, the senior defense official said, but decided against shooting down the balloon.

Secretary of Defense Lloyd J. Austin III called a meeting of senior military and defense officials on Wednesday to discuss how to handle the situation, the officials said.

Senior Biden administration officials called their Chinese counterparts with urgency using multiple channels, the senior defense official said during a briefing at the Pentagon.

China has several satellites that orbit around 300 miles above the earth. Like American spy satellites, the Chinese satellites can take pictures and monitor weapons launches, officials said. Both countries have a history of spying on each other; American officials visiting China on diplomatic missions routinely expect that their conversations will be monitored.

The Pentagon assessed that the spy balloon “did not provide anything that ‘other’ Chinese collections did not already provide them,” Michael P. Mulroy, a former deputy assistant secretary of defense, C.I.A. officer and Marine, said in a text message. “This was likely a reference to Chinese spy satellites.”

The revelation comes as tensions between Beijing and Washington have been on the rise. On Thursday, the Defense Department said the U.S. military was expanding its presence in the Philippines, as part of what military analysts said was an effort to constrain China’s armed forces and bolster the United States’ ability to defend Taiwan.

The Biden administration has aggressively moved to check China’s ability to further its technological and military ambitions, drawing fiery rebukes from Beijing. What U.S. officials view as China’s permissive stance toward the Russian invasion of Ukraine has also strained relations. But by far the most fraught issue between the two powers is Taiwan.

Mr. Blinken has rallied allies and partners to denounce China’s actions in Taiwan. At the same time, he is a proponent of President Biden’s goal of keeping open channels of communication with China to avoid a deterioration of the relationship.

Lawmakers were swift to call for the Biden administration to forcefully counter any threat.

“China’s brazen disregard for U.S. sovereignty is a destabilizing action that must be addressed, and President Biden cannot be silent,” House Speaker Kevin McCarthy, Republican of California, said in a Twitter post.

In a joint statement, Representatives Mike Gallagher, Republican of Wisconsin, and Raja Krishnamoorthi, Democrat of Illinois, said, “The Chinese Communist Party should not have on-demand access to American airspace.” The two added that the incident showed that the China threat “is not confined to distant shores — it is here at home, and we must act to counter this threat.”

Edward Wong and Julian Barnes contributed reporting.