WASHINGTON (AP) — The crowd pushed past the police barricades, up the steps to the iron doors and in what seemed like no time at all, hoisted a Trump flag from the U.S. Capitol.

“Protesters are in the building,” came the last words picked up by a microphone carrying a live feed of the Senate before it shut off.

Hundreds of President Donald Trump’s supporters paraded and hollered through some of the most hallowed spaces in the Capitol -- propped at the Senate dais and in the House speaker's office -- all to protest the election and keep President Donald Trump in office.

It was an extraordinary, unprecedented scene.

Trump, the defeated president, had been encouraging protesters as Congress convened for a joint session to certify Joe Biden’s win.

Under the very risers set up for Biden’s inauguration at the U.S. Capitol, the Trump supporters gathered.

Protests are typical at the Capitol. But this one was not.

At least one person was shot and killed, though it’s not clear who pulled the trigger during the chaotic scene. Some in the crowd were shouting “traitors” as officers tried to keep them back.

Inside the House chamber, lawmakers described a harrowing scene.

As they stayed down, they were told to have gas masks at the ready -- and take off the lapel pins they wear identifying them as elected representatives.

Police had guns drawn, and furniture barricaded the door.

Glass was shattered. Some prayed while protesters banged on the doors. Democratic Rep. Dean Phillips yelled loudly at Republicans, “This is because of you!”

A chaplain prayed as police guarded the doors to the chamber and lawmakers tried to gather information about what was happening.

Announcements blared: Due to an “external security threat,” no one could enter or exit the Capitol complex, the recording said. Lawmakers tweeted that they were sheltering in place.

Reporters and lawmakers hid under tables as the protesters banged on the door, demanding to be let inside. Rumors of guns spread but it wasn’t clear if any shots were fired beside the one. Tear gas was said to have been dispersed in the Rotunda.

After making sure the hallways were clear, police swiftly escorted people down a series of hallways and tunnels to a cafeteria in one of the House office buildings.

As he walked out of the Capitol, Connecticut Rep. Jim Himes said he “always assumed it could never happen here.”

But others were not so sure.

Rep. Mike Kelly of Pennsylvania, among those challenging Biden’s win, blamed “both sides” for the chaos at the Capitol.

“What do you think was taking place in this country?” he told reporters. “There’s been a lot of people during the last four years that have just been getting more and more incensed over what is going on around the country, on both sides. It’s just too bad. This is not how we handle things in America.”

The Senate side was not much different.

Vice President Mike Pence, who was presiding over the session, was evacuated from the Senate as protesters and police shouted outside the doors.

Police evacuated the chamber at 2:30 p.m., ushering senators to the first of what would be several undisclosed locations.

Clerks grabbed boxes of electoral college certificates as they left.

Vice President-elect Kamala Harris, attending the session, was among those ushered to safety.

As soon as they left, protesters roamed the halls shouting, “Where are they?” One got on the Senate dais and yelled, “Trump won that election.”