Several climate protesters were placed in restraints and escorted out of the Rayburn House Office Building on Wednesday, just ahead of a House Oversight Committee hearing featuring testimony from IRS whistleblowers.

The protest, according to footage captured by Fox News Digital, showed a little more than a dozen protesters walking through the hall outside the hearing wearing t-shirts that read: "End fossil fuels, Biden."

The demonstrators, many of whom marched down the hall chanting and raising their fists in the air, also displayed a large sign with the same message.

Upon reaching the hearing room, the protesters stopped outside the door and continued chanting loudly.

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Climate protestors

Climate protestors are placed in restraints inside of the Rayburn House Office Building on July 19, 2023. (Jon Michael Raasch)

The protesters were placed in restraints one by one and escorted out of the building by Capitol Police.

The protest came amid testimony offered to the House of Representatives by IRS whistleblowers who claim to have witnessed an "undeniable pattern of preferential treatment" for the Bidens, and "obstruction of the normal investigative process" throughout the years-long federal investigation into Hunter Biden.

The identity of the anonymous IRS whistleblower alleging political misconduct throughout the Hunter Biden investigation was revealed as special agent Joseph Ziegler — a gay Democrat with more than a dozen years serving within the agency’s criminal investigative division.

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IRS Whistleblower X Joseph Ziegler appears at House Oversight Committee hearing

IRS Criminal Investigator Joseph Ziegler testifies during a House Oversight Committee hearing related to the Justice Department's investigation of Hunter Biden on July 19, 2023, in Washington, D.C. (Drew Angerer/Getty Images)

Ziegler appeared for the first time publicly before the House Oversight Committee on Wednesday, alongside his IRS supervisor Gary Shapley, who also has blown the whistle on political influence surrounding prosecutorial decisions throughout the years-long federal probe into the president's son.

He said he is a 13-year special agent within the IRS’ Criminal Investigation Division and described himself as a "gay Democrat married to a man."

Ziegler is expected to testify that Hunter Biden "should have been charged with a tax felony, and not only the tax misdemeanor charge," and that communications and text messages reviewed by investigators "may be a contradiction to what President Biden was saying about not being involved in Hunter’s oversea business dealings."

Hunter Biden

Hunter Biden, the son of President Biden, arrives at Fort Lesley J. McNair in Washington, DC, on June 25, 2023. (Julia Nikhinson/Sipa/Bloomberg via Getty Images)

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He is expected to explain the "corrosion of ethical standards and the abuse of power that threaten our nation" that he has witnessed.

Ziegler is also expected to testify on several instances in which prosecutors "did not follow the ordinary process, slow-walked the investigation, and put in place unnecessary approvals and roadblocks from effectively and efficiently investigating the case," including prosecutors blocking questioning and interviewing of Hunter Biden’s adult children.

Fox News' Brooke Singman contributed to this report.