U.S. Rep. Dean Phillips took cover and reached for the gas mask under his seat on the floor of the U.S. House of Representatives on Wednesday afternoon as a riotous mob that had already breached the Capitol complex was about to break onto the House floor.

"This is because of you!" the Democratic lawmaker from Minnesota yelled in disbelief, his anger directed at Republican colleagues he felt bore responsibility.

"Run," Capitol police told Phillips and other members of Congress as they followed security through smoke-filled hallways echoing with loud screams and bangs to a secure location.

Minnesota's congressional delegation hunkered down around the Capitol complex as supporters of President Donald Trump broke into the building in an attempt to block them from certifying President-elect Joe Biden's victory.

Lawmakers posted on social media as the chaos unfolded, telling constituents they were safe and urging peace.

"We can't let these criminals that left such a stain on our country today win, and we will show them that by returning to that very chamber tonight, continuing our proceedings and fulfilling our obligation and certifying the election," Phillips said later, not long before the House and Senate returned for evening sessions.

Rep. Angie Craig was walking through the Capitol's tunnels to her office when people started breaking into the building. The Democratic congresswoman said she was told to lock herself in her office, turn off the lights and get out her gas mask.

She hid there as calls and texts streamed in from family, friends and constituents. Later, she and other lawmakers got an alert telling them to go to a secure location.

Craig estimated about 500 people were there and said the perimeter was guarded by law enforcement officers as they secured the building. The police presence around the Capitol had increased over the past few days in the lead-up to the protest, Craig said, but she called what happened a security breakdown.

"Today has been a failure. There is no way to characterize it as anything other than a failure," Craig said. "This isn't a peaceful protest. This is an attack, not only on Capitol property, but it really is an attack on our democracy."

Republican members of Minnesota's delegation, who had remained guarded about the Electoral College certification, offered no pushback to Trump's unsubstantiated claims of a rigged election but decried the storming of the Capitol.

"There is absolutely no excuse for violent and destructive protest. This type of behavior was unacceptable in Minneapolis and it is unacceptable today in Washington. Shameful," Republican Rep. Tom Emmer tweeted, along with a video of people clashing with police inside the Capitol.

Fellow Republican Reps. Pete Stauber, Michelle Fischbach and Jim Hagedorn similarly urged people to follow the law. "Please pray for our very brave Capitol Police and our great nation," Stauber said in a tweet. Fischbach said violence, particularly toward law enforcement personnel, is "unacceptable."

Hagedorn posted a series of comments on Twitter, saying that storming the Capitol is unacceptable and condemning the disruption.

"Many times, since being elected to Congress, I have voiced support for lawful protest, and have strongly condemned acts of violence and anarchy, routinely perpetrated by leftist activists. Today's protest in D.C., which led to a breach of the U.S. Capitol, brings the same response," Hagedorn wrote.

The four Minnesota Republicans split 50-50 as the House voted late Wednesday on a GOP-led objection to Arizona's electoral slate of electors. Emmer and Stauber were among a minority of House Republicans who voted against the GOP-led effort, while Hagedorn and Fischbach sided with the pro-Trump forces.

Stauber said earlier in the day that he was disappointed at the outcome of the election but felt it was not Congress' role to intercede. Fisch­bach, in a release that came just minutes before Trump supporters burst into the Capitol, said she believed there are too many allegations of voter fraud to certify the election.

None of Trump's claims of voter fraud have been substantiated, and multiple federal judges have rejected them.

A growing number of Democrats, meanwhile, were calling for Trump to be removed from office in the waning days of his presidency. Democratic Rep. Ilhan Omar called what happened a "coup attempt," and said she is drawing up Articles of Impeachment for Trump.

"This is not a one-off incident," Omar said in a prepared statement. "It is the result of years of collaboration on the part of the Republican Party, who have aided and abetted Trump's criminal attempts to destroy our republic, and the cause of democracy around the world."

Sen. Amy Klobuchar said she is committed to finishing the job Congress started Wednesday of counting the Electoral College vote.

"I've spoken with my colleagues, and our plan is that tonight we will finish our work. While this was a dark day in our nation's history, we will stand united in the face of those who seek to divide and sow chaos," Klobuchar said.

Democratic Sen. Tina Smith simply said she was safe and will continue to keep people posted.

Rep. Betty McCollum was in her office early Wednesday afternoon waiting for her turn to vote on the Electoral College certification when she heard Trump supporters were pushing down the barricades outside the Capitol.

McCollum said she and a staffer headed for the underground tunnels used to travel between buildings on the Capitol complex, hoping to get to a safer spot. But two doors from their planned exit, security told them the Capitol had been breached. They needed to immediately shelter in place.

"What a sad day in our democracy," McCollum said Wednesday evening from the office of a U.S. Senate colleague, where she was waiting for the all-clear to return to the vote. "We will have to do a deep oversight review on why we didn't have the security present to control the crowds that we should have had.

"In the meantime we need the president to stand up and tell the truth for the first time in four years and say he lost the election, and stop the madness," she said.

McCollum said she's very concerned about the next two weeks under Trump. She suggested he resign or Vice President Mike Pence step into the role.

Star Tribune staff writer Jim Spencer contributed to this report.