A group of nearly two dozen conservative Republican lawmakers stormed a secure meeting room in the basement of the U.S. Capitol on Wednesdsay, disrupting a Pentagon official's deposition in the impeachment inquiry into Donald Trump.

They staged a sit-in once inside, and had pizza and Chick-fil-A delivered for lunch, complaining all the while about a lack of transparency in the Democrats' secretive probe.

The president on Tuesday told Republicans in the Oval Office that he approved of their plan for a standoff, according to White House sources who spoke to Bloomberg.

Florida Rep. Matt Gaetz, who organized it, was not in the room. He insisted in text messages on Wednesday that Trump 'had no notice. ... I led the effort and never discussed with POTUS.'

Republicans who did attend Tuesday's White House meeting gave Trump a heads-up, according to a person familiar with what happened. Gaetz told reporters at the Capitol that there had been 'no coordination' with the White House.

Laura Cooper, the U.S. defense official who oversees Ukraine and Russia matters, was set to testify behind closed doors until the conservatives entered and began yelling.

Wednesday's dramatic confrontation led to a call to the House Sergeant-at-Arms, and the Capitol Police entering and trying to clear the room to bring order. The proceedings resumed five hours later.

The GOP group that had barged in brought cellphones with them, something that is forbidden in secure rooms known as SCIFs – Sensitive Compartmented Information Facilities. They are the most secure locations in the Capitol, where lawmakers routinely review classified intelligence.

Nearly two dozen House Republicans entered a Sensitive Compartmented Information Facility (SCIF) where a closed session before the House Intelligence, Foreign Affairs and Oversight committees was taking place at the U.S. Capitol

The Republicans stormed past guards and into the room, bringing cellphones into a space that's known for its tight security

Florida Rep. Matt Gaetz and other conservative Republicans held a press conference prior to bursting into the hearing room to call for transparency in Democrats' impeachment inquiry

White House aides said Wednesday that the group of conservative agitators had told Donald Trump on Tuesday about their plan to storm into a Capitol hearing room, uninvited, and the president gave the plan his blessing

Virginia Demorcatic Rep. Gerry Connolly told reporters that 'the SCIF is used by Congress for lots of classified, highly classified purposes. To compromise that to make a point is deeply troubling.'

'Failing all else, like the merits of the case, trying to defend the president effectively, they have now decided on physical disruption as their fallback,' he said.

The impeachment inquiry focuses in part on Trump's request for Ukraine to investigate a domestic rival, Democrat Joe Biden, leading Democrats to allege that he did it for his personal political benefit.

'They're freaked out. They're trying to stop this investigation,' liberal California Democratic Rep. Ted Lieu said. 'They don't want to hear from witness Cooper today. They know more facts are going to be delivered which are absolutely damning to the president of the United States.'

Conservative Republican Rep. Mark Meadows of North Carolina told reporters that there were 'about 20 members down there,' in the hearing room.

He said 'at least a dozen' of them don't sit on any of the three House committees engaged in the impeachment probe, 'and they're going to wait until there's a more open and transparent process.'

Republicans have called the rules for the impeachment inquiry set by the leaders of the Democratic-led House unfair. The U.S. Constitution gives the House wide latitude in how to conduct the impeachment process and set rules for the inquiry.

A witness who saw the events said the Republican lawmakers pushed past Capitol Police personnel and started yelling, voicing their objections to decisions made by the Democratic leaders of the House to hold depositions in closed sessions and not release transcripts of the testimony.

Workers delivered 20 pizzas and bottled soft drinks to the SCIF where Republicans had stormed a planned closed-door impeachment deposition

House Republicans spoke to reporters before storming the hearing room for their sit-in

Gaetz, an outspoken Trump supporter who led Wednesday's action, had tried to enter the committee room last week but was turned away because he was not a member of any of the three investigating committees – Foreign Affairs, Intelligence, and Oversight.

Liberal Democratic Rep. Alexandria Ocasio-Cortez of New York tweeted that Republicans who are members of the three committees have been permitted to participate in all the hearings.

'If these guys are so mad, maybe they should take their little flash mob to the @GOPLeader who didn’t assign them to the task,' she wrote.

Massachusetts Democratic Rep. Stephen Lynch, who is allowed to attend depositions as a member of the Oversight panel, said Cooper did not end up testifying on Wednesday. A House aide said the day's impeachment-related proceedings were suspended temporarily.

Democratic Rep. Eric Swalwell of California, a recent dropout from the 2020 presidential race, told reporters that Republicans had compromised a secure area of the Capitol, obstructed the impeachment inquiry and sought to intimidate a witness, but would not delay the impeachment probe overall.

'We see this a an effort not only to intimidate this witness but also to intimidate future witnesses from coming forward. It's not going to work,' Swalwell added. 'We're not going to be deterred,' Swalwell added.

Cooper, the deputy assistant secretary of defense for Russia, Ukraine and Eurasia, earlier in the day arrived for testimony and was expected to face questions about Trump's decision this year to withhold $391 million in security assistance to Ukraine that was approved by Congress.

In testimony on Tuesday, William Taylor, the top U.S. diplomat in Ukraine, said Trump had made the aid contingent on Ukraine announcing it would conduct politically motivated investigations the president demanded.

Trump on Monday told reporters that 'Republicans have to get tougher and fight' the impeachment, saying the Democrats 'vicious and they stick together.'

'It never ends. The Do Nothing Dems are terrible!' Trump wrote on Twitter earlier on Wednesday, later adding their 'case is DEAD!'

Before the hearing room was stormed, dozens of House Republicans appeared before reporters with some denouncing the impeachment process run by Democrats as a 'joke,' a 'railroad job,' a 'charade' and 'Soviet-style.' They complained that testimony was being taken privately rather than in public hearings and that the House did not hold a vote formally authorizing the investigation.

'It is a sham, and it's time for it to end,' North Carolina Republican Rep. Mark Walker said.

The inquiry could lead to the House passing formal charges known as articles of impeachment, prompting a trial in the Republican-controlled Senate on whether to remove Trump from office. Senate Republicans have shown little appetite for removing Trump.

As she arrived at the U.S. Capitol, Cooper did not answer questions from reporters. She apparently appeared voluntarily before the lawmakers as the Pentagon had not blocked her from testifying. The Trump administration had sought to block testimony by several other current and former officials.

Taylor testified that he was told by the U.S. envoy to the European Union, that Trump had linked the aid's release to public declarations by Ukrainian President Volodymyr Zelenskiy that he would investigate Biden, his son Hunter Biden's tenure on the board of a Ukrainian energy company called Burisma, and a debunked conspiracy theory that Ukraine, and not Russia, meddled in the 2016 U.S. presidential election.

The impeachment inquiry, triggered by a whistleblower complaint against Trump by a person within the U.S. intelligence community, focuses on a July 25 telephone call in which Trump asked Zelenskiy to carry out those two investigations. Zelenskiy agreed during the call. The aid was later provided.

Federal election law prohibits candidates from accepting foreign help in an election.

So far, few of Trump's fellow conservatives have appeared inclined toward his removal, though there have been some cracks in their support. Senator John Thune, the Senate's No. 2 Republican, told reporters that the picture painted by Taylor's testimony 'based on the reporting that we've seen is not a good one.'