WASHINGTON >> The acting chief of the Capitol Police apologized to Congress today for the agency’s massive security failures Jan. 6, acknowledging during a closed-door briefing that the department knew there was a “strong potential for violence” but failed to take adequate steps to prevent what she described as a “terrorist attack.”

Yogananda D. Pittman, the acting chief of police, also confirmed that the Capitol Police Board, an obscure panel made up of three voting members, had initially declined a request two days earlier for National Guard troops and then delayed for more than an hour as the violence unfolded Jan. 6 before finally agreeing to a plea from the Capitol Police for National Guard troops, according to prepared testimony obtained by The New York Times.

In an extraordinary admission, Pittman, who was not the acting chief at the time of the siege, told members of the House Appropriations Committee, which oversees funding for the agency, that the Capitol Police “failed to meet its own high standards as well as yours.” She added, “I am here to offer my sincerest apologies on behalf of the department.” Pittman’s predecessor, Steven Sund, resigned after the riot.

Speaking by video conference in a virtual briefing, Pittman told the committee her department knew that militia groups and white supremacists organizations would descend on Washington.

“We also knew that some of these participants were intending to bring firearms and other weapons to the event,” she said. “We knew that there was a strong potential for violence and that Congress was the target. The department prepared in order to meet these challenges, but we did not do enough.”

She said the Capitol Police had 1,200 people working on-site when the attack occurred, which was “no match” for “the tens of thousands of insurrectionists.”

During the hearing, the commander of the District of Columbia National Guard told committee members that his authority to quickly deploy the guard was removed before the riot. Maj. Gen. William J. Walker said he had such authority for July 4, but the Pentagon required additional approval for a request for the Guard during the Capitol attack, according to a person familiar with the testimony.

Walker testified that Sund called him as the threat to the Capitol increased Jan. 6 and that he immediately notified the Army.