The commanding general of the Washington, DC, National Guard testified on Wednesday that he received a phone call from the then-acting chief of the Capitol Hill Police frantically seeking help from the Guard to hold off the crowd of former President Donald Trump’s supporters at the US Capitol on Jan. 6 and alerted “Army senior leadership” of the request.

Maj. Gen. William Walker told senators investigating the Capitol riot in his opening remarks that the assistance sought by Steven Sund wasn’t approved until hours later.

“Immediately after the 1:49 pm call with Chief Sund, I alerted the Army Senior Leadership of the request. The approval for Chief Sund’s request would eventually come from the Acting Secretary of Defense and be relayed to me by Army Senior Leaders at 5:08pm – 3 hours and 19 minutes later,” Walker said in his remarks.

“We already had Guardsmen on buses ready to move to the Capitol. Consequently, at 5:20pm (in under 20 minutes) the District of Columbia National Guard arrived at the Capitol. We helped to re-establish the security perimeter at the east side of the Capitol to facilitate the resumption of the Joint Session of Congress,” he said.

Walker is among officials from Homeland Security, the Justice Department and the Pentagon who have been called to testify about missteps involved in preparing for and responding to the Capitol riot, as the Senate continues its investigation into the events on Jan. 6.

The national security officials are being grilled by senators about their lack of preparedness, even as there was public chatter on social media platforms about a  plan to gather in Washington, DC, and disrupt congressional lawmakers as they certified the Electoral College vote for President Biden.

The mob marched to the Capitol, overran law enforcement officials and made their way into the building, marauding through the halls and vandalizing many of the lawmakers’ offices.

Hearings so far have centered on efforts to gather and share intelligence about the rioters’ plans leading up to Jan. 6 and why the National Guard was delayed in deploying to assist besieged law enforcement officers and regain control of the situation.

Officials who testified at a hearing last week – including acting Capitol Police Chief Yogananda Pittman – described lapses in communication between law enforcement agencies that left officers to fend for themselves.

The acting chief of Washington, DC’s police force Robert Contee told senators he was “stunned” by the slow response in deploying the National Guard to the riot, even as congressional lawmakers fled to secret locations to seek safety from the unruly mob.

He testified that Sund pleaded with DC and Pentagon officials to send the Guard.

Contee said the officials reacted not by immediately deploying the troops, but by “asking about … the plan, the optics, how this looks with boots on the ground on the Capitol.”

Sen. Amy Klobuchar, the chairwoman of the Senate Rules Committee, said as the National Guard’s response was hampered, officers trying to keep the mob from breaching the Capitol were beaten and eventually swamped.

“Any minute that we lost, I need to know why,” Klobuchar told the Associated Press.

She said the panel was especially keen to hear from Walker about the events leading up to Jan. 6.

FBI Director Christopher Wray told senators at a hearing Tuesday that the agency passed along “raw, unverified” intelligence warning of the attack on the Capitol and Washington police on Jan. 5.

Wray also admitted he hadn’t read the report, picked up by an FBI field office in Norfolk, Va., until “days after the 6th.”