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

Sen. Jeff Merkley, D-Ore., tweeted a picture of what appears to be the mahogany boxes holding the Electoral College certificates that were the focus of the joint session -- forced to a halt when pro-Trump protesters stormed the building earlier just as debate on Arizona's vote count was underway.

The boxes are safe, per the senator, who added, "If our capable floor staff hadn’t grabbed them, they would have been burned by the mob."