Under heavy pressure from his advisers, President Trump on Wednesday released a five-minute video recorded in the Oval Office condemning last week’s mob violence at the Capitol and urging his supporters to stand down from further rioting next week.

The video was made public hours after Mr. Trump was impeached a second time and was the result, advisers said, of his realization of the catastrophic fallout from the deadly siege, which also left lawmakers fearing for their lives in the seat of American democracy.

The video was released on a White House Twitter account.

The president offered no note of humility, regret or self-reflection about his two months of false claims that the election was stolen from him. But it was also a broader condemnation of the violence than he has offered so far.

A week ago, hours after the rampage began, Mr. Trump told his supporters who had stormed the Capitol: “We love you. You’re very special.”

The president’s aides have warned him that he faces potential legal exposure for the riot, which was committed by his supporters immediately after a speech in which he urged them to “fight” the results of the election. The House impeached him on a single article, accusing him of “inciting violence against the government of the United States.”

Several officials urged Mr. Trump to shoot the video, with Jared Kushner, the president’s son-in-law and adviser, enlisting aides and even Vice President Mike Pence to tell him it was the right move. After it was recorded and posted, Mr. Trump still had to be reassured, according to administration officials.

The release of the video, which was recorded after the House impeachment vote, came after the president’s company, the Trump Organization, faced canceled contracts in New York, and after Senator Mitch McConnell, Republican of Kentucky and the majority leader, told allies he was pleased by the Democrats’ impeachment efforts and let it be known publicly that he was considering voting to convict the president in a Senate trial.

“As I have said, the incursion of the U.S. Capitol struck at the very heart of our republic,” Mr. Trump said. “It angered and appalled millions of Americans across the political spectrum.”

“I want to be very clear: I unequivocally condemn the violence that we saw last week,” he added. “Violence and vandalism have absolutely no place in our country. And no place in our movement. Making America great again has always been about defending the rule of law” and supporting law enforcement officials.

“Mob violence goes against everything I believe in and everything our movement stands for. No true supporter of mine could ever endorse political violence,” he said.

“If you do any of these things you are not supporting our movement. You are attacking it and you are attacking our country,” Mr. Trump said. “We cannot tolerate it.”

But Mr. Trump did not mention the name of President-elect Joseph R. Biden Jr., he did not concede the election and he did not talk about Mr. Biden’s inauguration, which is to take place next week under extraordinary security because of the threats inspired by the Capitol breach. He also made no mention of the impeachment vote.

He did, however, use the video to denounce what he called restrictions of free speech, referring not just to social media platforms that have banned him but alluding to the assertion that Republican House members made to argue against his impeachment.

The aides most involved in the language of the video were the White House counsel, Pat A. Cipollone; his deputy, Pat Philbin; and Mr. Trump’s main speechwriter, Stephen Miller.

During the day, Mr. Trump watched the impeachment debate in the House at various points and told advisers he was furious with Mr. McConnell and felt blindsided by him. Yet his deeper anger was at the House minority leader, Representative Kevin McCarthy of California, for publicly condemning him, people close to him said.

His relationship with his personal lawyer Rudolph W. Giuliani, who encouraged him to believe conspiracy theories about widespread election fraud, has frayed, one adviser said. The president was offended by Mr. Giuliani’s request for $20,000 a day to represent him in the election fight, which Mr. Giuliani denied making but which was in writing, and told aides not to pay him at all, an adviser to Mr. Trump said, confirming a report by The Washington Post.

White House officials have started blocking Mr. Giuliani’s calls to the president, another adviser said.

As lawmakers cast their impeachment votes, the president awarded medals to performers such as Toby Keith and Kay Coles James, the president of the Heritage Foundation, an official said. He was pleased that the Republican defections were fewer than some of his aides had anticipated.

The president was not raging behind closed doors, according to administration officials, although he was so far refusing to agree to a plan that would dedicate a series of days this week to the work of his final four years.

On Air Force One on Tuesday, during a trip to the southern border at Alamo, Texas, the president repeatedly said of the election to people traveling with him, “I won.”

Some advisers discussed the possibility of Mr. Trump resigning a few days early, in part because it would allow him to have the option of running again in 2024 and perhaps avoid the risk of being convicted and barred from future office by the Senate.

But the president has been dismissive of any suggestion that he leave the presidency early and told White House aides that President Richard M. Nixon, whose influence in the party ended when he resigned, did not have much to show for it.

Advisers said that Mr. Trump had to be dissuaded from going to the House floor to try to defend himself during Wednesday’s impeachment proceedings, something he wanted to do during his first impeachment in December 2019, advisers said.

Mr. Trump has also left open the possibility of pardoning himself, despite concern from Mr. Cipollone and warnings from outside advisers that he would inflame investigators who are already pursuing him.

Mr. Trump has never been more isolated than this week. The White House is sparsely staffed, according to people who went to work there on Wednesday. Those who did go to work tried to avoid the Oval Office.

More and more staff members have quit, and the White House Counsel’s Office is not preparing to defend him in the Senate trial. His political adviser, Jason Miller, posted on Twitter a poll from one of the campaign’s pollsters, John McLaughlin, that was intended to show the president’s grip on the party, as House Republicans debated their votes.

Plans to move Mr. Trump to another platform online after he was banned by Twitter have been halted. One option was the platform Gab, which has been a host for extremists and QAnon conspiracy followers. Gab was favored by Mr. Trump’s adviser Johnny McEntee, but blocked by Mr. Kushner, according to people familiar with the discussions, which were reported earlier by Bloomberg News.

Mr. Giuliani is also facing recriminations because of his involvement in inciting the mob that assaulted the Capitol. A group of former assistant U.S. attorneys who worked with Mr. Giuliani when he served as a federal prosecutor in Manhattan sent him a letter on Wednesday expressing dismay with his behavior at the rally before the siege.

The group said that Mr. Giuliani’s comments, in which he urged Trump supporters to engage in “trial by combat” to stop the certification of the election results, contributed to the loss of life and damage done to the country.

“It was jarring and totally disheartening to have seen one of our former colleagues engage in that conduct,” the former prosecutors said in the letter, which was signed by many Giuliani colleagues, including Kenneth Feinberg, Ira Lee Sorkin, Elliot Sagor and Richard Ben-Veniste.

“We unequivocally repudiate and denounce what you said: It is utterly destructive of all that we value,” they wrote, urging him to do what Mr. Trump did in the video and explicitly call on the president’s supporters to “stand down.”

“It is important that you do so at this very moment not only because it would be the right thing to do,” they continued, “but also to mitigate the risk of greater violence and minimize further damage to our democratic institutions and our democracy.”