As the chaotic scene continued in the nation's capital with the world watching, Trump once again tweeted his repeated his false claim that the presidential election was being stolen from him and appeared to try to justify the storming of the U.S. Capitol that he encouraged earlier in the day.

"These are the things and events that happen when a sacred landslide election victory is so unceremoniously & viciously stripped away from great patriots who have been badly & unfairly treated for so long," he said.

"Remember this day forever!" he added.

Former President George W. Bush released a statement on what he called an "insurrection" at the U.S. Capitol, calling it "a sickening and heartbreaking sight."

"This is how election results are disputed in a banana republic – not our democratic republic. I am appalled by the reckless behavior of some political leaders since the election and by the lack of respect shown today for our institutions, our traditions, and our law enforcement," Bush said.

"The violent assault on the Capitol – and disruption of a Constitutionally-mandated meeting of Congress – was undertaken by people whose passions have been inflamed by falsehoods and false hopes. Insurrection could do grave damage to our Nation and reputation. In the United States of America, it is the fundamental responsibility of every patriotic citizen to support the rule of law. To those who are disappointed in the results of the election: Our country is more important than the politics of the moment. Let the officials elected by the people fulfill their duties and represent our voices in peace and safety," Bush continued.

He did not mention President Trump by name.

Ahead of the district-wide curfew, the entire D.C. National Guard, FBI Washington Field Office, U.S. Secret Service, Federal Protective Services and the Metropolitan Police Department are responding to the breach at the U.S. Capitol to assist Capitol Police, sources tell ABC News. Deputy U.S. Marshals are also being deployed to assist, according to a Justice Department official. Customs and Border Protection officers are being deployed as well.

Washington, D.C., Mayor Muriel Bowser issued a curfew beginning at 6 p.m. and ending Thursday at 6 a.m. earlier in the day -- but with minutes to go until that curfew, there are hundreds of pro-Trump supporters still on the streets, resisting calls from law enforcement and lawmakers to go home.

After nearly four hours of pro-Trump supporters breaching the building, officials have declared the U.S. Capitol is secure.

Here are images of what’s unfolding:

Sen. Joe Manchin, D-W.V., just told reporters on Capitol Hill that the Senate intends to finish certifying the election this evening.

"We're going to finish tonight," Manchin said. "Everyone is committed to staying whatever it takes to get our job done."

"These thugs are not running us off," he added.

Manchin told reporters he believes that they will be able to continue debate in the Capitol building.

He said that being in the secure holding room with other Senators had a "way of bringing us together."

-ABC News' Trish Turner and Allie Pecorin

House Speaker Nancy Pelosi, in a new letter to Democrats on Saturday, asked members to prepare to return to Washington this week -- another signal that the House could take up and pass the impeachment article to the Senate after it is formally introduced on Monday.

Pelosi thanked fellow Democratic representatives for speaking with her on a conference call Friday and said she was taking their considerations into account. She did not specifically mention voting on impeachment in the letter, though.

"Since that call, I have received scores of communications from Members expressing your views about how we go forward and regarding a strong presence of our Caucus in the Capitol," she wrote. "Over the last few days, I have discussed your views with Constitutional lawyers, both inside and outside the Congress, to consider the parliamentary and constitutional options available to us."

"From what I have heard from Members, and from the deluge that I have received from the public, it is clear that, once again, the Times Have Found Us to save our democracy," Pelosi added in the letter. "We will be proceeding with meetings with Members and Constitutional experts and others. I continue to welcome your comments. I urge you to be prepared to return to Washington this week."

While Democrats are hopeful Republicans will back their effort, none have come out and said they would back the charge as drafted.

Pelosi said at a press conference on Thursday, "If the Vice President and Cabinet do not act [on the 25th Amendment], the Congress may be prepared to move forward with impeachment."

Some Democrats planned to connect with Republican colleagues this weekend to gauge their support and encourage them to back the effort.

-ABC News' Benjamin Siegel