Washington DC - Then US President Donald Trump did not leave his personal dining room for most of the time a violent mob raged at the Capitol on January 6, 2021, the House committee investigating the insurrection said in its prime-time hearing Thursday.

"He refused to defend our nation and our Constitution. He refused to do what every president must," Republican Vice Chair Liz Cheney said.

Focusing on Trump's inaction, the panel has provided a moment-by-moment account of the 187 minutes between when the attack on the US Capitol began and when the president released a video on Twitter urging his supporters to withdraw.

Trump became aware of the violent mob immediately after his speech at the Ellipse near the White House, said Congresswoman Elaine Luria, who led the hearing with Congressman Adam Kinzinger.

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"Within 15 minutes of leaving the stage, President Trump knew that the Capitol was besieged and under attack," Luria said.

Instead of taking action, Trump walked into his private dining room next to the Oval Office and watched coverage of the attack on Fox News for two hours, and made calls to senators and his attorney Rudy Giuliani.

Records of the president's daily movements and phone logs show no entries between when Trump returned to the White House and when he released a video telling supporters to go home at 4:17 PM.

"There is no official record of what President Trump did while in the dining room... The chief White House photographer wanted to take pictures because it was, in her words, 'Very important for his archives and for history.' But she was told, quote, 'No photographs,'" Luria said.

White House Counsel Pat Cipollone said in a clip from his deposition with the committee that soon after the violence began, he, Chief of Staff Mark Meadows, Trump's daughter Ivanka, and White House lawyer Eric Herschmann all pleaded with Trump to issue a statement telling the mob to leave.

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The committee showed other video of top-ranking national security and White House officials saying one by one that Trump did not speak to leaders of the Defense Department, National Guard, FBI, Homeland Security, or the Secret Service. Trump also didn't communicate with Washington DC Mayor Muriel Bowser or Capitol Police.

In a clip from his deposition, Chairman of the Joint Chiefs of Staff Mark Milley questioned why Trump didn't act.

"You're the commander in chief," Milley said. "You've got an assault going on on the Capitol of the United States of America, and there's nothing? No call? Nothing? Zero?"

"The mob was accomplishing President Trump's purpose, so of course he didn't intervene," Kinzinger said. "President Trump did not fail to act during the 187 minutes between leaving the Ellipse and telling the mob to go home. He chose not to act."

Thursday's witnesses were former White House press aide Sarah Matthews and former deputy national security adviser Matthew Pottinger, who were at the White House on January 6 and resigned over Trump's actions.

Pottinger served on the National Security Council throughout Trump's presidency and was one of the highest-ranking officials to resign that day. The former Marine intelligence officer served in the White House for four years and was in the vicinity of the Oval Office at various points throughout the day.

Matthews worked in Congress and for the Trump campaign before serving as deputy press secretary. She stressed that Trump could have walked from the dining room, where he stayed for hours during the riot, to the White House press room in just 60 seconds, and noted that staff could have quickly assembled the White House press corps in the Oval Office so he could make a public statement.

She said Trump's 2:24 PM tweet, which attacked Vice President Mike Pence for not agreeing to reject the electors of certain states, was pouring gasoline on a fire.

"It was essentially him giving the green light to these people, telling them that what they were doing at the steps of the Capitol, and entering the Capitol, was okay, that they were justified in their anger," she said.

The tweet was sent while the Secret Service was trying to move Pence out of his ceremonial office outside the Senate chamber to an underground garage where his motorcade was waiting.

A former White House official with national security responsibility, who was granted anonymity by the committee, gave chilling details of what was coming over the Secret Service radio as Pence and his family were evacuated.

"Members of the VP detail at this time were starting to fear for their own lives" and there were calls to "say goodbye to loved ones" because the security team thought things were "about to get very ugly," the person said.

In her opening statement, Cheney said that the hearings had brought forward new tips, witnesses and evidence, and that the investigation would continue.

"Doors have opened, new subpoenas have been issued, and the dam has begun to break," she said.

Over the previous seven hearings this summer, the committee has made the case that Trump knew he had fairly lost his bid for a second term but chose to churn up accusations of a stolen election anyway, and that he pressured state legislatures and Pence to break the law to keep him in power.