A Chinese balloon that flew across the US was able to gather intelligence from several military sites and transmit it back to Beijing in real time, despite the Biden administration's efforts to prevent it from doing so.
BC News reported that the high-altitude balloon, controlled by Beijing, was able to make multiple passes over some of the sites before it was shot down on February 4.
At times it was flying in a figure-eight formation, NBC said, citing two current senior US officials and one former senior administration official.
The three officials said it could transmit the information it collected back to Beijing in real time.
"The intelligence China collected was mostly from electronic signals, which can be picked up from weapons systems or include communications from base personnel, rather than images," NBC cited the officials as saying.
White House official John Kirby told reporters on Monday that he could not confirm NBC's report, but said the US limited the balloon's "ability to be able to collect anything additive".
He added that the US government was able to study and analyse the balloon while it was in US airspace, saying "we gained some useful context".
The Chinese Foreign Ministry in Beijing and the Chinese Embassy in Washington did not immediately respond to requests for comment.
At the time, US officials played down the balloon's impact on national security.
The balloon, which Beijing denies was a government spy vessel, spent a week flying over the US and Canada early in February before the US military shot it down off the Atlantic Coast on President Joe Biden's orders.
The incident prompted US Secretary of State Antony Blinken to postpone a planned visit to Beijing and further strained relations between Washington and Beijing.
The episode caused an uproar in Washington and led the US military to search the skies for other objects that were not being captured on radar.
The US said on February 17 it had successfully concluded recovery efforts off South Carolina to collect sensors and other debris from the suspected Chinese surveillance balloon and that investigators would analyse its "guts".