Woman Fatally Shot as Pro-Trump Protesters Break Into U.S. Capitol

3:23 PM PT -- A police spokesperson tells us the woman shot has died.

1:15 PM PT -- At least one person has been shot during the mayhem, a video from inside shows a woman -- draped in a Trump flag -- on the floor after a gun goes off. Law enforcement sources tell us the woman was transported to a local hospital in critical condition. Her current condition is not known.

What's more ... protesters outside The Capitol set up a makeshift noose -- and one of them got into Rep. Nancy Pelosi's office, kicked his feet up and left a note that read, "We will not back down."

Additionally, law enforcement found multiple explosive devices around D.C. ... including one at the RNC HQ, which they safely detonated.

Trump finally tweeted, "I am asking for everyone at the U.S. Capitol to remain peaceful. No violence! Remember, WE are the Party of Law & Order – respect the Law and our great men and women in Blue. Thank you!"

12:12 PM PT -- This is the wild scene INSIDE the Congressional chamber ... a protester has actually made it to the dais and pumped his fist in the air. He reportedly yelled, "Trump won that election!"

There was also an armed standoff on the Senate floor as one or more protesters attempted to break through a barricaded door. You can see security forces inside had their guns drawn, prepared for the worst.

11:59 AM PT -- Congress members are now being evacuated from the building, and they're leaving with something more than just regular face coverings on their mugs -- gas masks have been issued as well.

Florida congressman Michael Waltz got on the horn with Fox News WHILE he and his colleagues were being ushered out of the House floor by authorities -- this after protesters infiltrated the building and were roaming the halls with cops on their tail.

He says tear gas has been deployed inside, and as such ... all Senators and Representatives were given gas masks for protection. Waltz took a moment amid the chaos to condemn the actions of the protesters, saying a debate about the Constitution (which is what he says was going on while they were in session) is one thing, but trying to hatch a raid like the one unfolding is reprehensible ... and downright un-American.

Seems like this Biden vote might have to happen some other day.

11:29 AM PT -- Some protesters have made their way into the Capitol Building itself, and are literally just steps away from the Senate chamber.

Footage and photos show a handful of demonstrators who've actually breached the front doors and walked up a flight of stairs and corridors with their hands up ... presumably, because cops inside have their guns drawn.

The certification vote was put on pause, and Pence was escorted out of the room. Looks like things still aren't under control ... the session briefly resumed, but is now on hold again.

As for what President Trump is doing after lighting this fuse? Tweeting, of course. He said, "Please support our Capitol Police and Law Enforcement. They are truly on the side of our Country. Stay Peaceful!"

Not sure what he means by staying peaceful ... as protesters had already stormed the Capitol when he tweeted. Too little, too late.