(CNN) The acting head of the US Capitol Police told congressional members during a closed-door briefing Tuesday that the "department failed to meet its own high standards" on January 6 when a crowd of pro-Trump rioters overran the Capitol building.
Acting US Capitol Police chief Yogananda Pittman called the insurrection a "terrorist attack" and offered her "sincerest apologies on behalf of the department," according to her prepared remarks during a briefing for lawmakers on the House Appropriations Committee with a number of agencies that had a role in security on January 6.
Pittman also said the department was aware of a "strong potential for violence" targeting Congress and did not take the appropriate steps to prevent it.
Pittman's admission comes as US Capitol Police officers are debating whether to hold a no-confidence vote targeting department leaders who were working on the day of insurrection, including Pittman. One source told CNN that Pittman was the operational chief the day of the siege at the Capitol and "never took control of the radio or commanded officers what to do in any way, shape or form."
Officers have told CNN that they felt abandoned and betrayed by the department's leadership.
"Let me be clear: the Department should have been more prepared for this attack," Pittman said Tuesday. "By January 4th, the Department knew that the January 6th event would not be like any of the previous protests held in 2020. We knew that militia groups and white supremacists organizations would be attending. We also knew that some of these participants were intending to bring firearms and other weapons to the event."
Ultimately, Pittman took responsibility for mistakes that were made in protecting the Capitol.
"As the Acting Chief, I take responsibility for the mistakes that were made by the Department, and I pledge to this Committee, the Congress, the American people, and my USCP colleagues, that we will do better going forward, but we need to make changes," she said.
Acting Sergeant at Arms Timothy Blodgett issued a blunt assessment Tuesday of the security failures that occurred, both in preparing for a protest of this nature and reacting to events as they unfolded, according to his prepared statement during Tuesday's briefing in front of lawmakers.
"It is clear there was a failure of preparation. Whether it was insufficient or conflicting intelligence, lacking ability to translate that intelligence into action, insufficient preparation or an inadequate ability to mobilize partner agencies for immediate assistance, a series of events, once thought unfathomable, unfolded allowing our most sacred halls to be breached. And, sadly, several lives were lost, including Officer Brian Sicknick and Officer Howard Liebengood," Blodgett said in his remarks.
Pittman outlined four things that made the department ill-equipped to respond to the attack, including the lack of manpower. The acting chief said USCP officers did not have the right equipment on hand or easily accessible, and the process for sealing the building "may not have been consistently followed." Lastly, Pittman stated that the department was told that communication over their radios and the public address system were hard to hear during the attack.
Since the insurrection, Pittman said USCP has coordinated with the National Guard to secure the Capitol and the complex surrounding it and has "taken steps to ensure" that USCP is sharing and receiving critical intelligence information from its law enforcement partners. Pittman also said that the department's intelligence director is now holding daily internal intelligence briefings with USCP officials.
Pittman said that going forward, "the Capitol's security infrastructure must change and that the Department needs access to additional resources -- both manpower and physical assets."
This story has been updated.