(CNN) Roughly two-dozen House Republicans on Wednesday stormed a closed-door deposition in secure House Intelligence Committee spaces to rail against the Democratic-led impeachment inquiry , a political stunt ratcheting up the GOP complaints about the process that delayed Wednesday's scheduled deposition for five hours.

The conservative lawmakers, led by Republican Rep. Matt Gaetz of Florida, barged into the deposition and demanded they be allowed to see the closed-door proceedings where members of three committees planned to interview Deputy Assistant Defense Secretary Laura Cooper as part of the impeachment probe into President Donald Trump.

The chaotic scene, with Republicans flouting House rules to make a political point, represented a new and more confrontational phase of the Republican attack on House Intelligence Chairman Adam Schiff and the Democratic impeachment investigation.

By early afternoon, pizza and snacks were being brought into the committee area. The Republicans in the committee SCIF — short for a sensitive compartmented information facility -- left around 2 p.m. ET to attend House votes, apparently ending the protest.

The deposition then began around 3 p.m. ET, lawmakers said, a roughly five-hour delay, and lasted less than four hours before Cooper left the Capitol.

Deputy Assistant Secretary of Defense for Russia, Ukraine, and Eurasia Laura Cooper arrives at the US Capitol ahead of her closed-door deposition in Washington, DC on Wednesday.

Once Cooper's testimony began, she provided a very technical readout of how foreign aid is disbursed, according to lawmakers. Several lawmakers say her testimony helped show that the Ukraine aid deviated from that normal process. Cooper, who was issued a subpoena in the same manner as State Department officials who have testified, did not give an opening statement, lawmakers said.

A chaotic scene in a secure room

The real fireworks happened before she started speaking.

A source in the room said that as Cooper was sitting down to testify, the Republicans stormed through the room's three different doors. Rep. Bradley Byrne of Alabama was yelling at Schiff, but the California Democrat did not engage, the source said. Other Democrats, including Rep. Val Demings of Florida, shouted back at both Byrne and Republican Rep. Louie Gohmert of Texas, who were yelling about the process.

Demings, according to one source in the room, asked Republicans if they were trying to teach their children "that it's OK to lie, steal and cheat so long as you don't get caught?"

"Don't you have any work to do today?" she said to one Republican member, according to the source.

Cooper left the room while the Republicans refused to vacate the space. The source said the Capitol Police and sergeant at arms were consulted when members refused to leave the room.

"It was closest thing I've seen around here to mass civil unrest as a member of Congress," said one source in the room.

White House met with Republicans on Tuesday

The Republicans even walked into the hearing room with their electronics, according to Democratic Rep. Gerry Connolly of Virginia, which is prohibited in the space, a secure room used for discussing and handling classified information. GOP Rep. Mike Conaway of Texas, who is on the House Intelligence Committee, collected the electronics.

"All of us put our electronics in boxes outside," Connolly said. "That SCIF is used by Congress for lots of highly classified purposes. To compromise that to make a point, is deeply troubling."

A committee official described it as a "major security breach," and Schiff told reporters later Wednesday he was concerned about the integrity of the SCIF, though he did not elaborate.

"The President's allies in Congress are trying to make it even more difficult for these witnesses to cooperate but we're grateful that the witness is a real professional and has come forward, notwithstanding the obstacles," Schiff said.

Among the Republicans participating in the protest was Minority Whip Steve Scalise of Louisiana, the No. 2 House Republican. Gaetz and Scalise both suggested they might return at some point to protest further, though they did not do so Wednesday.

The storm-the-room stunt came two days after Trump said that he thought Republicans "have to get tougher and fight." Many of the Republicans engaged in the protest were at a White House on Tuesday meeting with Trump, and a person familiar with the matter told CNN that Trump had advance knowledge of the plans to enter the space.

GOP Rep. Mark Meadows of North Carolina and House Freedom Caucus Chairman Andy Biggs, however, said Wednesday's protest was not raised at the meeting with Trump.

The press conference that preceded the sit-in had been in the works for a week, according to one Republican lawmaker, who said they had anticipated beforehand that the event would be a traditional press conference and didn't realize until the event began that the group would push into the secure area.

House Republicans gather to speak at a news conference organized by GOP Rep. Matt Gaetz of Florida on Capitol Hill on Wednesday in Washington, DC.

Republicans say they forced their way in because Democrats are holding impeachment depositions behind closed doors, denying the public the ability to see what's being said by witnesses that could be used to impeach Trump.

"Show your face where we can all see the travesty that you are trying to foist on America and the degradation of our Republic that you're engaged in," said Rep. Mo Brooks of Alabama.

Rep. Jim Jordan, the top Republican on the Oversight Committee who has been in all of the depositions so far, said the Republican disruption was justified because "it's finally reached a boiling point where members just said they are so frustrated at the idea that they can't be a part of this and see what's going on."

But the GOP complaints about the process — Republicans who have been in the room have made the same argument about public hearings and releasing transcripts following nearly every deposition — comes as Republicans have focused their objections on the process rather than the substance of what the witnesses have said.

A day after Taylor's explosive testimony

The GOP disruption comes one day after the committees heard from the top US diplomat in Ukraine, Bill Taylor, who told lawmakers in a lengthy opening statement that Trump had demanded Ukraine launch an investigation to help him politically before US security aid to Ukraine would be released, undercutting White House claims there was no quid pro quo with Ukraine.

Some Republicans in Congress have expressed concerns with Trump's conduct following Taylor's testimony — though others like Jordan have argued Taylor did not establish a quid pro quo — as Republicans continue to press Democrats to change how they conduct the impeachment inquiry.

"The picture coming out of it, based on the reporting that we've seen, I would say is not a good one," said Sen. John Thune of South Dakota, who as the majority whip is a member of Senate GOP leadership. "But I would say also that until we have a process that allows for everybody to see this in full transparency, it's pretty hard to draw an hard and fast conclusions."

But many Republicans in Congress remain fiercely loyal to Trump.

Brooks responded to questions about his reaction to Taylor's testimony by arguing that just hearing "bits and pieces" of testimony means "you're apt to be fooled."

"We don't know whether what he said is true or not because of the sham processes being used," Brooks said. "We have a judicial system, we have a bill of rights that are designed to guarantee a process so that fact-finders have the best chance of reaching the true conclusion."

Democrats say that Republican complaints about the process are simply unwarranted. Republicans on the three committees — Intelligence, Foreign Affairs and Oversight — have equal time to question witnesses.

Schiff has said that the committee will release transcripts and hold public hearings, but said they are conducting the fact-finding part of the investigation, like a grand jury before a trial, that's done behind closed doors.

Republican Rep. Andy Biggs of Arizona speaks at the podium during a news conference on Capitol Hill outside the closed-door deposition related to the House's impeachment inquiry on Wednesday.

He's argued that keeping witness testimony private in the early stages prevents other witnesses from learning what others are saying and aligning their stories.

Democrats also pointed to the Benghazi Select Committee run by former Rep. Trey Gowdy, a South Carolina Republican who conducted closed-door hearings in that investigation.

"This (investigation) clearly has far too much fact for their comfort level, so they have to stop it from moving forward," said Rep. Debbie Wasserman Schultz, a Florida Democrat who was in the room when the Republicans barged in.

Rep. Eric Swalwell, a California Democrat on the Intelligence Committee, said that the Republican tactics would not deter the impeachment investigation.

"The tactics are an effort to delay the inevitable. They are a response to just damaging and pulverizing testimony yesterday," Swalwell said.

This isn't the first time that Gaetz has tried to enter the House Intelligence Committee spaces during a deposition. He did the same thing last week during a deposition and left after the House parliamentarian said he could not stay because he was not on the committees.

But this time he brought allies and made clear he wouldn't go quietly, leading to the chaotic scene that played out Wednesday.

This story has been updated with additional developments Tuesday.