Key Points:
- Debris from a suspected Chinese spy balloon that was shot down over the US has been recovered.
- US officials say it was part of a major spy program that targeted 40 countries.
- China has not answered questions as to what government department or company the balloon belonged to.
China's balloon that crossed the United States was equipped to collect intelligence signals and was part of a huge, military-linked aerial spy program that targeted more than 40 countries, the US government says.
A fleet of balloons operates under the direction of the People's Liberation Army (PLA) and is used specifically for spying, outfitted with high-tech equipment designed to collect sensitive information from targets across the globe, the US said.
Similar balloons have floated over five continents, according to the administration.
The statement from a senior US State Department official offered the most detail to date linking China's military to the balloon that was shot down by the US military last weekend over the Atlantic Ocean.
The public details are meant to reject persistent denials from Chinese officials that the balloon was used for spying, including a claim on Thursday that US accusations about the balloon amount to "information warfare" against China.
In Beijing, before the US offered new information, Chinese foreign ministry spokeswoman Mao Ning repeated her government's insistence that the large unmanned balloon was a civilian meteorological airship that had blown off course and that the US had "overreacted" by shooting it down.
"It is irresponsible," Ms Mao said.
The latest accusations, she said, "may be part of the US side's information warfare against China".
China's defence minister refused to take a phone call from US Defence Secretary Lloyd Austin to discuss the balloon issue on Saturday, the Pentagon said.
The FBI said much of the evidence remains underwater. Source: AAP, EPA / US Navy/Mass Communication Specialist 1st Class Tyler Thompson
"It's very early for us in this process, and the evidence that has been recovered and brought to the FBI is extremely limited," one of the officials told reporters in a briefing about its role in processing the wreckage of the balloon.
Officials said the FBI still did not have access to the majority of the balloon's "payload" where most of the onboard electronics were likely carried.
The FBI said much of the evidence remains underwater and that it has begun decontaminating some of its remains by removing salt and seawater.
"We have not identified any sort of any energetic or offensive material," one of the FBI officials said, when asked whether any explosives or other harmful components had been identified from the balloon.
China has not answered questions as to what government department or company the balloon belonged to or how it planned to follow up on a pledge to take further action over the matter.
The US offered a flatly contradictory characterisation to China of the balloon and its purpose.
It said imagery of the balloon collected by US U-2 spy planes as it crossed the country showed that it was "capable of conducting signals intelligence collection" with multiple antennas and other equipment designed to upload sensitive information and solar panels to power them.
Jedidiah Royal, the US assistant defence secretary for the Indo-Pacific, told a Senate Appropriations subcommittee that the military has "some very good guesses" about what intelligence China was seeking.
More information was expected to be provided in a classified setting.
The State Department official who provided details to reporters by email did so on condition of anonymity due to the sensitive nature of the matter, which had already forced the cancellation of a planned visit to China by Secretary of State Antony Blinken.
The official said an analysis of the balloon debris was "inconsistent" with China's explanation that it was a weather balloon that went off course.
The US is reaching out to countries that have also been targeted, the official said, to discuss the scope of the Chinese surveillance program and is looking into potential action that "supported the balloon's incursion into US airspace".
The official said the US has confidence that the manufacturer of the balloon shot down on Saturday has "a direct relationship with China's military and is an approved vendor of the" army.
The official cited information from a PLA procurement portal as evidence for the connection between the company and the military.