(CNN) Biden administration officials disclosed new information Thursday about the capabilities of the suspected Chinese surveillance balloon that traversed the United States last week and what they are learning as the FBI begins analyzing the parts recovered after the balloon was shot down Saturday.
US officials also detailed what they've discovered about the broader spying operation they say the Chinese government has undertaken using a fleet of high-altitude surveillance balloons across the globe.
But senior Biden officials faced pointed questions on Capitol Hill from lawmakers in public hearings and classified briefings as Congress is demanding more information about why the balloon wasn't shot down sooner.
Here's what we learned Thursday about the balloon.
A senior State Department official said Thursday that the balloon "was capable of conducting signals intelligence collection operations" and was part of a fleet that had flown over "more than 40 countries across five continents."
The Biden administration has determined that the Chinese balloon was operating with electronic surveillance technology capable of monitoring US communications, according to the official.
"We know the PRC used these balloons for surveillance," the official said. "High-resolution imagery from U-2 flybys revealed that the high-altitude balloon was capable of conducting signals intelligence collection operations."
Signals intelligence refers to information that is gathered by electronic means -- things like communications and radars.
The FBI has started its initial stages of evaluating the pieces of the balloon that were recovered and brought to the FBI lab in Quantico, Virginia for analysis, senior FBI officials said Thursday.
Only evidence that was on the surface of the ocean has been delivered to FBI analysts so far, one official said, which includes the "canopy itself, the wiring, and then a very small amount of electronics." The official said analysts have not yet seen the "payload," which is where you would expect to see the "lion's share" of electronics.
The officials added that understanding the components of the balloon is vital intelligence and could be "important pieces of evidence for future criminal charges that could be brought."
Despite the latest revelations about the capabilities of the spy balloon, the Pentagon has insisted since the vessel was first acknowledged publicly that it does not give China capabilities above and beyond what they already have from spy satellites or other means.
"We did not assess that it presented a significant collection hazard beyond what already exists in actionable technical means from the Chinese," said Gen. Glenn VanHerck, the commander of US Northern Command and NORAD, on Monday.
Administration officials from the Pentagon, State Department and intelligence community briefed lawmakers on Capitol Hill Thursday on the balloon, which has prompted criticism from Republicans over allowing it to float across the US before it was shot down off the Atlantic coast.
Lawmakers were told Thursday that the order to send the balloon was dispatched without Chinese President Xi Jinping's knowledge, sources familiar with the briefing said.
The idea Xi was unaware of the balloon "is the working theory and an ongoing intelligence gap," a source briefed on the matter later told CNN. This is among the things the intelligence community is actively working on, the source said, making clear it's far from a definitive assessment.
The officials told lawmakers that the US has assessed that little new intelligence was gleaned by the Chinese balloon operation because the Chinese appeared to stop transmitting information once the US learned of the balloon, in addition to US measures to protect sensitive intelligence from China's spying operations, according to the sources.
The US also believes what they have recovered from the shot-down balloon is beneficial to US intelligence, the sources said.
Another source familiar with the briefings said officials said the balloon would give the Chinese better photos and signals collection than satellites, as well as a better ability to steer and hover longer over collection targets.
The Biden officials told Congress that it's still unclear what the motivation was for the flight of the balloon across the US, which prompted Secretary of State Antony Blinken to postpone his trip to China. One of the sources said that the US believes senior leadership of the People's Liberation Army and Chinese Communist Party including Xi were also unaware, and the US believes the Chinese are still trying to figure out how this happened.
In the classified congressional briefings, the administration officials argued that the US didn't move earlier to shoot down the balloon in part over fears it could provoke an escalation of military tensions with China or even a military conflict. Biden gave the order to shoot down the balloon whenever the Pentagon felt it was safe to do so, the sources said, so the Pentagon ultimately made the call on when to shoot it down.
The officials told lawmakers one of the reasons the balloon was not first shot down when it entered Alaskan airspace is that the waters there are cold and deep, making it less likely they could have recovered the balloon, according to the sources.
The House briefing Thursday morning was tense, the sources said, with several Republicans railing against the administration, including GOP Rep. Marjorie Taylor Greene of Georgia, who said that the Pentagon made the president -- whom she noted she doesn't like -- look weak by their actions.
In response, the briefers tried to lay out a detailed timeline of the actions, the sources said.
"The Pentagon was telling us they were able to mitigate in real-time as this was taking place and I believe that's accurate," Rep. Mike Quigley, an Illinois Democrat, told CNN."I believe the preeminent concern they had, as they expressed in real time, was the safety of US citizens."
After the briefing, House Speaker Kevin McCarthy said it was wrong for the Biden administration to wait to shoot down the balloon.
"They should have never let it into our sovereignty, they should have taken it another time," McCarthy told CNN.
But Republican Sen. Mitt Romney told CNN he believes the US made right decision to wait before shooting it down.
"I believe that the administration, the president, our military and intelligence agencies, acted skillfully and with care. At the same time, their capabilities are extraordinarily impressive. Was everything done 100% correctly? I can't imagine that would be the case of almost anything we do. But I came away more confident," Romney said Thursday.
Senators pushed defense officials at an Appropriations Committee hearing on Thursday over the military's assessment of the Chinese surveillance, with Democratic Sen. Jon Tester of Montana telling officials that he did not know how they could unequivocally say it was not a military threat.
"You guys have to help me understand why this baby wasn't taken out long before and because I am telling you that that this ain't the last time. We've [seen] brief incursions, now we've seen a long incursion, what happens next?," said Tester, the chairman of the Senate Appropriations Defense Subcommittee.
"We don't understand because quite frankly, we have been briefed in his committee over and over and over again, about the risks that China poses, both economically and militarily," he said. "China tends to push the envelope all the time until a line is set down.""
Pentagon officials said at the hearing that the Defense Department was not concerned about the balloon gathering intelligence over Alaska as it was not near sensitive sites.
The balloon first crossed into US airspace over Alaska on January 28, Melissa Dalton, assistant secretary of defense for Homeland Defense and Hemispheric Affairs, said during the hearing. When the balloon was spotted, it was not determined to have "hostile intent," said Lt. Gen. Douglas Sims, director of operations for the Joint Chiefs of Staff, and officials did not believe it would impact aviation routes or present a significant intelligence gathering ability. That changed when the balloon began drifting over the lower 48 states, but while it was over Alaska, officials determined it was not over critical infrastructure.
The House on Thursday passed a symbolic resolution condemning China's surveillance balloon with a vote of 419 to zero.
The FBI investigation into recovered balloon is the first of its kind in the bureau's history, senior FBI officials familiar with the operation said Thursday as they described the initial stages and what's been recovered so far.
The officials said that this is the first time the FBI has investigated a spy balloon of this nature and assisted with the processing of such a scene. The officials added that understanding the components of the balloon is vital intelligence and could be "important pieces of evidence for future criminal charges that could be brought."
The parts of the balloon recovered on the surface of the ocean have been delivered so far, while recovering additional pieces of the balloon that sunk has been complicated by bad weather, officials said.
It's not yet clear where the balloon's parts were manufactured, the officials said, including whether any of the pieces were made in America. Because analysts have yet to look at the bulk of the equipment on the balloon, the officials said that there has not been a determination as to everything the device was capable of doing and its specific intent.
Of the small portion they have examined, analysts have not identified any sort of explosive or "offensive material" that would pose a danger to the American public.
The FBI was alerted to the balloon on February 1, the officials said, because the intelligence community had determined that the balloon had an electronic element to it. By late Sunday -- the day after the balloon was shot down -- agents had arrived at the scene, and the first pieces of recovered evidence arrived at the FBI lab in Quantico on Monday.
There was English writing on parts of the balloon that were found, one of the sources familiar with the congressional briefings said, though they were not high-tech components. The source declined to provide detail on what specific parts of the balloon contained English writing.
Bloomberg News first reported that components of the balloon had English writing on them.
The State Department official said the balloon was part of a Chinese fleet developed to conduct surveillance operations" with a manufacturer tied to China's People's Liberation Army (PLA), the official added.
The official suggested that the US is eyeing sanctions for the presence of the balloon in US airspace -- which US officials have repeatedly called a violation of US sovereignty and international law -- noting the US "will also explore taking action against PRC entities linked to the PLA that supported the balloon's incursion into US airspace."
A recovery operation to secure debris from the balloon is ongoing with analysis continuing at an FBI laboratory in Virginia, but the officials' remarks suggest the US has already established the balloon was operating with electronic surveillance technology.
However, the US has said it has been able to prevent the balloon from intercepting US communications.
"The high-altitude balloons' equipment was clearly for intelligence surveillance and inconsistent with the equipment onboard weather balloons. It had multiple antennas to include an array likely capable of collecting and geo-locating communications. It was equipped with solar panels large enough to produce the requisite power to operate multiple active intelligence collection sensors," the official added.
"We could track the exact path of the balloon and ensure no activities or sensitive unencrypted comms would be conducted in its vicinity," a senior administration official said this week. "The US military took immediate steps to protect against the balloon's collection of sensitive information, mitigating any intelligence value to the PRC."
President Joe Biden suggested Wednesday that bilateral relations with China had not been affected by the balloon fallout, but China reacted angrily to the shootdown, refusing a call with Secretary of Defense Lloyd Austin, and Secretary of State Antony Blinken canceled a high-stakes trip to Beijing on Friday. New sanctions in response to the balloon would likely further inflame tensions.
"We know these balloons are all part of a PRC fleet of balloons developed to conduct surveillance operations. These kinds of activities are often undertaken at the direction of the People's Liberation Army (PLA)," the senior State Department official added.
China "has overflown these surveillance balloons over more than 40 countries across five continents," the State Department official said, noting that "the Biden Administration is reaching out to countries directly about the scope of this program and answer any questions."
The official said that based on China's "messaging and public comments, it's clear that they have been scrambling to explain why they violated US sovereignty and still have no plausible explanation -- and have found themselves on their heels."
"As we saw with the second balloon over Central and South America that they just acknowledged, they also have no explanation for why they violated the airspace of Central and South American countries," the official said. "The PRC's program will only continue to be exposed, making it harder for the PRC to use this program."
This story has been updated with additional details.