Congressional leaders have pointed fingers at the agency.

The acting chief of the Capitol Police apologized to lawmakers in a closed-door briefing on Tuesday for not being more prepared for the Jan. 6 attack on the U.S. Capitol.

“Let me be clear: the Department should have been more prepared for this attack,” acting Chief Yogananda Pittman told the House Appropriations Committee on Tuesday, in opening remarks obtained by ABC News. “We knew that there was a strong potential for violence and that Congress was the target.”

“I am here to offer my sincerest apologies on behalf of the Department,” she said in the remarks.

Pittman confirmed that the panel supervising the Department, the Capitol Police Board, rejected a request from then-Capitol Police chief Steven Sund two days before the riot for National Guard troops.

The Washington Post previously reported that the Capitol Police request was rejected by congressional security officials because they anticipated House and Senate leaders wouldn’t want troops stationed around the Capitol.

Capitol Police activated more officers to work on Jan. 6 in anticipation of violence – including a SWAT team and civil disturbance units – but “we did not do enough,” Pittman said.

Sund also asked permission to bring in the National Guard on Jan. 6, but was not granted authorization from the board “for over an hour,” Pittman told the House committee.

Pittman also called the attack on the Capitol a “terrorist attack by tens of thousands of insurrectionists determined to stop the certification of Electoral College votes, the Department failed to meet its own high standards as well as yours.”

“I do believe certain challenges the Department faced the day of the attack could have been overcome with additional preparation,” she writes.

Pittman also said that once the Capitol was breached their focus turned to the safety of members and leadership.

A source familiar confirmed that the chiefs and assistant chiefs went silent on Jan. 6 Neither took control of the radio, the source said, and when officers were looking for leadership, there was none.

Capitol Police Union Chairman Gus Papathanasiou told ABC News that there is currently no vote of no confidence underway against the acting chief and senior department leadership.

“Officers have been calling for a vote of no confidence since January 6th,” Papathanasiou said. “At this time we have not initiated a vote of no confidence. Doesn’t mean we can’t think about it. There’s a big difference.”