Impeachment article has 200 cosponsors: US rep.

“The White House grieves the loss of life that occurred yesterday and extends sympathies to their families and loved ones. We also continue to pray for a speedy recovery for those who suffered injury," the statement read.

Four people present during Wednesday's riots and the pro-Trump mob storming the Capitol have died, according to Washington, D.C. Metropolitan Police Department Chief Robert Contee. One woman was shot and killed by a U.S. Capitol Police officer when Trump supporters breached the building, forcing a lockdown with members of Congress inside. Another woman and two men suffered “medical emergencies” and subsequently died.

Neither Trump nor anyone more senior than Deere at the White House has publicly commented on the deaths.

-ABC News' Ben Gittleson

Former White House chief of staff Mick Mulvaney has resigned from his position as U.S. special envoy to Northern Ireland, telling CNBC during an interview Thursday morning he called Secretary of State Mike Pompeo Wednesday night with the news.

“I can't do it. I can't stay,” Mulvaney said. “It's a nothing thing. It doesn't affect the outcome. It doesn't affect the transition. But it's what I've got, right, and it's a position I really enjoy doing. But you can't do it. And I wouldn't be surprised to see more of my friends resign over the course of the next 24 to 48 hours."

Asked if, in retrospect, he considered himself an enabler of Trump, he said “it’s a fair question.”

“The answer is I don't know what I feel yet, entirely. I can tell you this, there are, most of us, almost all of us, except I guess the people who are on the inner circle right now who didn't sign up for what you saw last night.”

He said all of Trump’s “successes” -- “all of that went away yesterday, and I think you’re right to ask the question as to how did it happen.”

Mulvaney went on to say the issue now is that Trump’s inner circle consists of people like trade adviser Peter Navarro and personal attorney Rudy Giuliani.

“Clearly he is not the same as he was eight months ago, and certainly the people advising him are not the same as they were eight months ago, and that leads to a dangerous sort of combination as you saw yesterday," he said. "I imagine a lot of folks in the building, a lot of folks who served him from the beginning who are no longer in the beginning, are asking the same things this morning."

-ABC News' Ben Gittleson

It was bad, unspeakably and unfathomably so -- utter lawlessness and disorder, carnage in the seat of American government, happening with the seeming encouragement of the outgoing president.

It could have been worse. It might still get there, even with President Trump's statement Thursday morning pledging "there will be an orderly transition on January 20th."

Until Wednesday's siege, when a mob of extremists engaged in an attempted insurrection and violent occupation of the Capitol, there seemed to be little cost to some Republicans in indulging Trump's conspiracy theories, lies and fantasies.

That fiction was exposed by Wednesday's horror. The trauma of the day saw seemingly sincere concerns about election security melt away, amid a newfound bipartisan resolve to finish final certification of Biden's victory.

Now, there's something approaching bipartisan unity in disgust for Trump's behavior through the post-election period. Denunciations and even some resignations are flowing in more steadily after Tuesday's Georgia runoff losses and Wednesday's repulsive events.

"Remember this day," Trump tweeted Wednesday. He will surely get that wish.

Even aside from impeachment and 25th Amendment talk, Trump will be an ex-president in 13 days. The fact is that getting rid of Trump is the easy part.

Cleansing the movement he commands, or getting rid of what he represents to so many Americans, is going to be something else.

-ABC News' Political Director Rick Klein

Rep. Markwayne Mullin, R-Okla., said he witnessed the moment a police officer fatally shot a woman inside the U.S. Capitol on Wednesday, as Trump supporters stormed the building.

Mullin said the shooting happened as an angry, pro-Trump mob that had been protesting outside broke into the Capitol building and attempted to force entry into the House chamber, which was still in session.

"They were trying to come through the front door, which is where I was at in the chamber, and in the back they were trying to come through the speaker's lobby, and that's problematic when you're trying to defend two fronts," Mullin told ABC News Chief Anchor George Stephanopoulos in an interview Thursday on "Good Morning America."

"When they broke the glass in the back, the (police) lieutenant that was there, him and I already had multiple conversations prior to this, and he didn't have a choice at that time," Mullin said. "The mob was going to come through the door, there was a lot of members and staff that were in danger at the time. And when he [drew] his weapon, that's a decision that's very hard for anyone to make and, once you draw your weapon like that, you have to defend yourself with deadly force."

A U.S. Capitol Police officer in plainclothes fired his service weapon as "multiple individuals" tried to gain access to the House room, striking a woman. She was transported to a local hospital where she was pronounced dead, according to Robert Contee, chief of the Metropolitan Police Department of the District of Columbia. Authorities have not yet released the woman's identity.

Mullin said police "showed a lot of restraint" and "did the best they could."

"That young lady's family's lives changed and his (the officer's) life also changed," Mullin said. "But what also happened is that mob that was trying to go through that door, they left. And his actions will may be judged in a lot of different ways moving forward, but his actions I believe saved people's lives even more. Unfortunately, it did take one though."

Mullin said he "never thought" he would witness such a scene unfold in the United States.

"I get people being passionate and being frustrated, but there's a right way and and wrong way to do things and yesterday was wrong. There was absolutely no excuse for it," he said. "We're very fortunate a lot more people didn't actually lost their life. One is way too many."