The acting chief of the U.S. Capitol Police warned lawmakers Thursday that militia members involved in the Jan. 6 riot “want to blow up the Capitol and kill as many members as possible” during President Biden’s first congressional address.

The stark warning about another potential threat to Congress — which has not been corroborated by other law enforcement agencies — comes as a date for Biden’s first address on Capitol Hill has not been set. New presidents typically deliver a speech to a joint session of Congress in February.

Acting chief Yogananda D. Pittman told lawmakers there was “a direct nexus” between the threats and a Biden speech.

She cited that intelligence to explain why National Guard members who were deployed and the tall security barriers that were erected around the Capitol after the insurrection have not yet been removed.

Acting chief Yogananda D. Pittman, right, is seen at the Capitol earlier this month. (Erin Schaff/The New York Times/Pool/Associated Press)

“Based on that information, we think that it’s prudent that Capitol Police maintain its enhanced and robust security posture until we address those vulnerabilities going forward,” Pittman said.

It was not clear whether other agencies have also identified threats to the Capitol during Biden’s first congressional address. An FBI spokeswoman declined to comment. The bureau is regularly tipped to online chatter about all manner of threats, and officials have said it is difficult to separate that which is aspirational from that which poses real concern.

Troubling online conversation often fails to materialize into a tangible threat. In the run-up to Biden’s inauguration, for example, the FBI privately warned law enforcement agencies that far-right extremists had discussed posing as National Guard members in Washington, and that others have reviewed maps of vulnerable spots in the city. Officials took aggressive measures to secure the Capitol, and ultimately the day passed without incident.

But officials are eager to show they are taking threats seriously, particularly because lawmakers from both parties have criticized the Capitol Police and the FBI for not responding to indications of possible violence before the Jan. 6 riot. An internal Capitol Police intelligence report three days before the siege warned “Congress itself” could be the target of violence, and an FBI office in Virginia warned one day before that demonstrators were prepared for “war.”

Pittman insisted Thursday there was “no credible threat” in the available intelligence that rioters would actually break into the Capitol. As a result, she said, the police “were not prepared” for the demonstration to turn into an angry mob, as she said a small subset of organized rioters whipped up the others present to increasing displays of aggression and violence.

And she said that “well in excess” of 10,000 people came onto the Capitol grounds during the Jan. 6 insurrection, and that about 800 entered the building — the first time an official has provided an estimate of the size of the crowd that broke through the Capitol’s perimeter.

“To stop a mob of tens of thousands requires more than a police force, it requires physical infrastructure or a regiment of soldiers,” Pittman said. “We know that some of those temporary enhancements are not popular, but these are necessary in the short term.”

Lawmakers, especially those in the GOP, are growing antsy over the continued presence of soldiers and barriers at the Capitol, which Rep. Jaime Herrera Beutler (R-Wash.), the top Republican on the Appropriations subcommittee hosting Thursday’s hearing, said is costing $2 million per week to maintain.

Rep. Mark Amodei (R-Nev.) described the reinforcements as “stark visual sadness” and likened the current Capitol environment to “working in a minimum security prison.”

In the Senate, Rules Committee ranking member Roy Blunt (R-Mo.) also said Thursday that “there are ways to achieve the safety we need here without the fortresslike sense at the Capitol right now, and hopefully you get there sooner rather than later.”

This was the first week that current and former officials responsible for the response to the shortlived insurrection testified in public before congressional committees, the opening acts of what is likely to be a long-term effort to document the failings that led to the violence and avoid a similar calamity in the future.

So far, those hearings have failed to resolve even basic questions about what transpired, such as when the Capitol Police chief requested approval for backup from the National Guard.

Former Capitol Police chief Steven A. Sund and former House sergeant-at-arms Paul Irving, both of whom resigned following the riot, clashed over some details of the timeline that day. Sund claimed he had requested help from the National Guard two days before the riot and again as soon as the pro-Trump demonstrators broke through the outdoor security perimeter, requesting the Guard by 1:09 p.m. that day.

Irving told lawmakers he was on the floor of the House at that time and did not remember getting a call from Sund until nearly 1:30 p.m., when Sund told him he might be requesting the Guard be activated.

On Thursday, Pittman partially backed up Sund’s account, reading from his cellphone records that she said showed that he repeatedly contacted Irving, starting at 12:58 p.m. that day.