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

At District of Columbia Mayor Muriel Bowser's request, Army Secretary Ryan McCarthy has activated about 340 unarmed D.C. National Guardsmen to assist local law enforcement with the demonstrations taking place on Wednesday pegged to the Electoral College certification.

"We think it's helpful to have our D.C. Guardsmen, who are our Guard, that I have requested from the Secretary of the Army to assist MPD [Metropolitan Police Department] with traffic management," Bowser said Monday. "It absolutely frees up more officers."

The D.C. Guard is unique in that any call-ups have to be made by the Army secretary and not the jurisdiction’s top elected official -- as is the case with state governors. Additionally, more focus has been given to the call-ups since the controversial presence of D.C. Guardsmen and the use of D.C. Guard helicopters during the Black Lives Matter demonstrations last summer.

"They will be deployed to assist us with crowd management, as well as traffic control in our nation's capital that will allow for the police officers to focus on anyone who's intent on instigating agitating or participating in violence in our city," said D.C. Police Chief Robert Contee. He also labeled any possibility of violence surrounding the protests as "unacceptable" and repeated that carrying firearms is not allowed under D.C. law.

A senior defense official said Bowser put in the request for Guardsmen on Dec. 31 and that it was approved Monday morning. Beginning Tuesday through Thursday, the 340 personnel will help man 30 traffic control checkpoints around the northern side of the downtown area close to the National Mall.

"No one's going to be armed or body armor or anything like that," said the official. "What they need is traffic control."

-ABC News' Luis Martinez and Quinn Owen