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."

After hours of chaos and as the Virginia State Police arrived at the U.S. Capitol Building, Trump called on his supporters to "go home" in a one-minute video message posted to Twitter.

Trump still didn't concede his loss to Biden and, without evidence, called the election "stolen" and fraudulent," but told the protesters to go home "in peace."

"I know you're hurt. We had an election that was stolen from us. It was a landslide election, and everyone knows it, especially the other side. But you have to go home now. We have to have peace. We have to have law and order we have to respect to our great people in law and order. We don't want anybody hurt."

"It's a very tough period of time. There's never been a time like this where such a thing happened where they could take it away from all of us from me from you from our country. This was a fraudulent election. But we can't play into the hands of these people. We have to have peace."

"So go home. We love you. You're very special. You've seen what happens. You see the way others are treated that are so bad and so evil. I know how you feel -- but go home and go home in peace," he said.

President-elect Joe Biden, who was scheduled to deliver afternoon remarks on the economy, addressed the unrest at the U.S. Capitol on Wednesday afternoon from Wilmington, Delaware, and called on Trump to "step up" and condemn the chaos being committed in his name.

"I call on President Trump to go on national television now, to fulfill his oath and defend the Constitution and demand an end to this siege," Biden said. "To storm the Capitol, to smash windows, to occupy offices, the floor of the United States Senate, rummaging through desks -- on the Capitol, on the House of Representatives -- threatening the safety of duly elected officials, it's not a protest. It's insurrection."

"The world is watching," he continued. "Think what our children watching television are thinking. Think what the rest of the world is looking at. For nearly two and a half centuries, we the people, in search of a more perfect union, have kept our eyes on that common good. America is so much better than what we’ve seen today."

Former Republican New Jersey Gov. Chris Christie called on President Donald Trump to ask protesters to leave the Capitol grounds on ABC News Live.

"It’s pretty simple," he said. "The President caused this protest to occur. He's the only one who can make it stop."

"What the vice president just said is not good enough, what the president said is not good enough," Christie added. "The President has to come out and tell his supporters to leave the Capitol grounds, and to allow the Congress to do their business peacefully. Anything short of that is an abrogation of his responsibility."

Christie noted that both Trump and his son Donald Trump Jr. had previously spoken to the crowd.

"I don't know that they anticipated this was going to be the result," he said. "But it doesn't matter whether they did or they didn’t. This is the result of their words."

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