The leaders reviewed the threat profile of the Chinese stratospheric balloon and possible response options, and ultimately decided not to recommend taking it out kinetically, because of the risk to safety and security of people on the ground from the possible debris field. Pentagon leaders presented the options to President Joe Biden on Wednesday.

A senior administration official confirmed that Biden had been briefed and received a “strong recommendation” that the balloon not be shot down.

“Instances of this activity have been observed over the past several years, including prior to this administration,” said the senior administration official. “We acted immediately to protect against the collection of sensitive information.”

Biden did not respond to a question from reporters about the balloon on Thursday afternoon at the White House.

“Currently we assess that this balloon has limited additive value from an intelligence collection perspective over and above what the PRC can do through other means,” the senior defense official said. “Nevertheless we are taking all necessary steps to protect against foreign intelligence collection of sensitive information.”

The official said the balloon does not pose a threat to civil aviation because of its altitude.

The official said the U.S. military will continue to monitor it closely and will keep the option of taking out the balloon on the table.

“We are tracking it in minute detail in real time and we will constantly update our assessment,” the official said. “We are in constant surveillance of this thing through a bunch of different means.”

The official said there was a window while the balloon was over Montana Wednesday when they could have taken it down. NORAD sent aircraft — including F-22 Raptors from Nellis Air Force Base and airborne early warning aircraft known as AWACs — but the official would not say whether one of the options was to shoot the balloon out of the sky with a U.S. aircraft.

The U.S. military flights prompted a ground stop at the airport in Billings, with air traffic controllers citing a “special military mission.”

The U.S. is confident the balloon belongs to China, the official said, and they have communicated to the Chinese government “through multiple channels both here in D.C. and in Beijing.” The official did not say whether the Chinese admitted the balloon was theirs.

This type of activity is not unprecedented, the senior defense official said, with China flying stratospheric balloons like this before, but the difference this time is the balloon is staying over the U.S. longer than usual.

The stratosphere starts between 4 and 12 miles above the Earth’s surface and extends around 31 miles, according to the National Weather Service.

Chinese Foreign Ministry spokesperson Mao Ning said Beijing was assessing the situation and that speculation and hype were unhelpful while facts were still being clarified.

“China is a responsible country that always abides by international law and has no intention of infringing on any country’s territory and airspace,” Mao said at a daily briefing.

“We hope that both sides can handle this together calmly and carefully,” she added.

Tensions are high between the U.S. and China. 

On Thursday, the Pentagon announced it would bolster the U.S. military presence near Taiwan, with plans to expand the number of U.S. military personnel in the Philippines. Announced during Austin’s visit to Manila, the Enhanced Defense Cooperation Agreement (EDCA) designates four more bases where U.S. military personnel can now base in strategic areas of the country, adding to the five already authorized to house American troops.

“We’re not seeking permanent basing in the Philippines,” Austin said during a news conference Thursday.

Courtney Kube

Courtney Kube is a correspondent covering national security and the military for the NBC News Investigative Unit.

Carol E. Lee

Carol E. Lee is an NBC News correspondent.

Peter Alexander, Sally Bronston and Jennifer Jett contributed.