A group of House Republicans on Wednesday delayed the start of closed-door testimony by Laura Cooper, the top Pentagon official overseeing U.S. policy regarding Ukraine, after storming the secure room where the deposition was being held.

Led by Rep. Matt Gaetz, R-Fla., the GOP members — who don’t sit on the committees that are questioning witnesses in the impeachment inquiry — entered the secure room, known as a SCIF, in the basement of the Capitol Visitor's Center. Before entering, they protested Democrats' handling of the probe, arguing that the process was not fair to Republicans or the president.

House rules only allow members to participate in depositions if they serve on the committees.

Rep. Debbie Wasserman Schultz, D-Fla., told reporters that there were approximately 20 GOP members in the room who refused to leave, and said that they came into the secure room yelling that they be allowed inside. Some of these members brought their cellphones, which are not permitted.

"This is being held behind closed doors for a reason because they don’t want you to see what the witnesses are like,” Rep. Andy Biggs, R-Ariz., told reporters Wednesday morning before entering the room. “This is a Soviet-style impeachment process. This is closed doors, it is unfair in every way and I don’t care whether you are the president of the United States or any other citizen of this country, you should be allowed to confront your witnesses."

Rep. Adam Schiff, the chairman of the House Intelligence Committee who is leading the probe, explained last week that there is precedent stemming from the Watergate era, as well as President Bill Clinton’s impeachment proceedings, for holding the initial investigation behind closed doors. He also said that he anticipated a time when impeachment investigators will release the transcripts of the depositions, and that the House may call back some of those witnesses to testify in public.

On Wednesday, Biggs and other members appeared to post tweets from inside the room.

As part of a series of tweets, Biggs said that "when Republican members were in the SCIF, Chairman Schiff immediately left with the witness."

“Chairman Schiff threatened to file ethics complaints against remaining Republican members – not clear what exactly he would file or cite,” Biggs claimed.

Rep. Mark Walker, R-N.C., also tweeted from the room.

Cooper's appearance comes a day after the top U.S. diplomat in Ukraine, Bill Taylor, told members of Congress that President Donald Trump directed officials to tie aid to Ukraine to demands that the country open an investigation into the Biden family and the 2016 election, a potentially serious blow to Trump's repeated denials of a quid pro quo.

Lawmakers were expected to question Cooper about the Trump administration's decision over the summer to withhold the assistance to Ukraine that had previously been appropriated by Congress, despite the Pentagon’s recommendation that it be distributed.

Read the full story on NBC's website.