Updated

Protesters stormed the U.S. Capitol Wednesday afternoon in a major security breach as lawmakers were just starting the process of certifying the electoral win for President-elect Joe Biden.

The intrusion into both the House and Senate forced lawmakers to evacuate to secure locations. There was a least one shooting victim who was transported from the U.S. Capitol shortly before 3 p.m., Fox News has learned.

"This is a coup attempt," tweeted Rep. Adam Kinzinger, R-Ill.

One protester made it inside the Senate chamber and sat in the chair where Vice President Mike Pence was presiding, declaring Trump won the election, according to a pool producer.

Several dozen were roaming through the halls on the Senate side, yelling, "Where are they?"

The chaos and violence erupted at the Capitol as Republicans mounted their first challenge to Biden's victory within minutes of the counting of the Electoral College votes during a joint session of Congress on Wednesday. The formal objection set off a debate in both chambers and showed divisions between the GOP.

But the debate was cut short when supporters of President Trump breached the Capitol and forced a recess of both the House and the Senate due to a "security threat." Capitol Police advised members to move inside the nearest office and seek cover. Lawmakers were told to get escape hoods under their chairs and move to the Rotunda.

A Capitol security official announced over a speaker in the Senate: "Lock all doors if able. If unable, seek shelter or concealment. Remain calm and await further directions. I repeat ... security threats, security threats, security threats inside the US Capitol."

One lawmaker told Fox News the protesters breached the House chamber and there were reports of shots were fired at some point, but details were unclear. Images show protesters breaking windows outside the chamber and security officials pointing guns at them to try to stop them from entering. 

Police with guns drawn watch as protesters try to break into the House Chamber at the U.S. Capitol on Wednesday, Jan. 6, 2021, in Washington. (AP Photo/J. Scott Applewhite)

Police with guns drawn watch as protesters try to break into the House Chamber at the U.S. Capitol on Wednesday, Jan. 6, 2021, in Washington. (AP Photo/J. Scott Applewhite)

Another lawmaker, Rep. Scott Franklin, R-Fla., said lawmakers were evacuated.

"Security was breached and we've evacuated the chamber to a safe location," Franklin said. 

Pence had to be escorted out of the Senate chamber. Trump supporters were seen outside trying to break through the Capitol doors, according to a video posted by The Recount. And then protesters made it inside, carrying their American flags and Trump flags.

Trump urged the protesters to remain peaceful after the breach.

"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," Trump tweeted.

The vice president went further, urging protesters to leave the Capitol.

Pence tweeted, "The violence and destruction taking place at the US Capitol Must Stop and it Must Stop Now. Anyone involved must respect Law Enforcement officers and immediately leave the building." 

Images show a breach inside the Senate chamber, with protesters hanging from the balcony and taking over the chamber. 

Prior to the major security threat, Rep. Paul Gosar, R-Ariz., and Sen. Ted Cruz, R-Texas, submitted a joint objection to counting Arizona's 11 electoral votes for Biden. They issued a one-sentence written note on why the state's votes should be tossed out saying they were not "regularly given."

Rep. Paul Gosar, R-Ariz., objects to certifying Arizona's Electoral College votes during a joint session of the House and Senate convenes to count the electoral votes cast in November's election, at the Capitol, Wednesday, Jan 6, 2021. (AP Photo/Andrew Harnik)

Rep. Paul Gosar, R-Ariz., objects to certifying Arizona's Electoral College votes during a joint session of the House and Senate convenes to count the electoral votes cast in November's election, at the Capitol, Wednesday, Jan 6, 2021. (AP Photo/Andrew Harnik)

Pence, under tremendous pressure by Trump, acknowledged the objection met the requirements of being in writing and signed by one senator and one representative and he recessed the normally mundane session of counting electoral college votes so both the Senate and House could debate the validity of the Arizona results.

GOP lawmakers stood and cheered the objection being accepted, therefore stalling the all but inevitable certification of Biden's win.

Gosar said he was objecting on behalf of 60 GOP lawmakers. They intend to keep on objecting Republicans may object to the Electoral College votes of up to six states that Biden won: Arizona, Georgia, Michigan, Nevada, Pennsylvania and Wisconsin. 

As the House debated the Electoral College results, the crux of the GOP argument was that state executives and courts changed election rules in the midst of the coronavirus pandemic to allow expanded mail-in voting or registration windows when only state legislatures should do so. Therefore, the arguement goes, votes cast under these new voting systems are invalid.

"You cannot change the rules of an election while it is underway and expect the American people to trust it," said Rep. Lauren Boebert, R-Colo.

Democrats and many GOP senators balked at this last-minute effort to overrule voters and overturn a presidential election.

Senate Majority Leader Mitch McConnell, R-Ky., said the election wasn't even especially close and courts have resoundingly rejected Trump's legal claims, including "sweeping conspiracy theories," that the election was stolen from him. 

McConnell said his vote to certify Biden's election win will be the most important he's ever cast in his 36 years in the Senate.

"The voters, the courts, and the states have all spoken," McConnell said. "If we overrule them all, it would damage our republic forever."

The debate carried on as thousands of Trump supporters rallied outside the Capitol demanding the election results be tossed out. They were invigorated by a speech from Trump himself who again refused to concede his election loss and raised unsubstantiated claims of voter fraud that have been rejected by dozens of courts, state election officials and his own attorney general William Barr.

Trump has demanded loyalty from Pence to try to overturn the results in Congress, which he doesn't have the sole authority to do, and from his GOP allies. The long-shot effort could drag on for hours depending on how many states received valid objections that require debate.

Lawmakers prepare to put on masks on the floor of the House of Representatives as protesters enter the U.S. Capitol, Wednesday, Jan 6, 2021, in Washington. (AP Photo/Andrew Harnik)

Lawmakers prepare to put on masks on the floor of the House of Representatives as protesters enter the U.S. Capitol, Wednesday, Jan 6, 2021, in Washington. (AP Photo/Andrew Harnik)

Republicans leading the charge in House acknowledged in some way the pressure from voters to do something and polling showing that Republicans have doubts.

"Americans instinctively know there was something wrong with this election," said Rep. Jim Jordan, R-Ohio., citing Trump's crowd sizes and compared to Biden's smaller events.

"But somehow the guy who never left his house wins the election," Jordan said. 

Biden purposely held smaller gatherings and relied on virtual events due to the coronavirus pandemic. 

Democrats said the "free and fair" election wasn't even close. Biden won the popular vote and the electoral vote 306 to 232, and all of Trump's legal remedies were rebuked.

"That we are here with a substantial number of our members seeking to overturn an election is remarkable, tragic and all too predictable," said Rep. Adam Schiff, R-Calif., about Trump's claims for months of massive voter fraud.

"The 2020 election is over and the people have spoken," added Rep. Jamie Raskin, D-Md.

Fox News' Chad Pergram, Lillian LeCroy, Jason Donner and Kelly Phares contributed to this report.