Peter Strzok's hearing before Capitol Hill on Thursday quickly devolved into rancorous partisan bickering after the controversial FBI agent declined to answer questions about special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE's Russia investigation.

Strzok declined to answer the first question from Rep. Trey Gowdy Harold (Trey) Watson GowdySunday shows preview: Election integrity dominates as Nov. 3 nears Tim Scott invokes Breonna Taylor, George Floyd in Trump convention speech Sunday shows preview: Republicans gear up for national convention, USPS debate continues in Washington MORE (R-S.C.), the chairman of the House Oversight and Government Reform Committee, about how many people he interviewed in the first week of the federal Russia probe — on the instructions of the FBI general counsel.

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"Based on that, I will not answer that question because it goes to matters related to the ongoing investigation," Strzok told lawmakers.

House Judiciary Committee Chairman Bob Goodlatte Robert (Bob) William GoodlatteNo documents? Hoping for legalization? Be wary of Joe Biden Press: Trump's final presidential pardon: himself USCIS chief Cuccinelli blames Paul Ryan for immigration inaction MORE (R-Va.), who was overseeing the hearing, almost immediately stepped in, threatening contempt proceedings: "Mr. Strzok, you are under subpoena and are required to answer the question."

Strzok disputed the notion that he was there under subpoena, arguing that he appeared before the committees voluntarily.

"You have not stated a valid legal basis for not responding to a question from a member of the House of Representatives," Goodlatte replied.

Rep. Jerrold Nadler (D-N.Y.) tried to step in with "point of order" interjections repeatedly, stating that Republicans know he is not able to answer questions about an ongoing federal probe.

Goodlatte, however, batted down his objections as "not valid" and "not well taken."

Democrats continued to raise objections to Goodlatte, whose refusal to entertain them drew outraged disbelief and laughter from the other side.

"The chairman is not being proper," Nadler said of Goodlatte.

"The chairman is being proper," Goodlatte replied.

An exchange between Gowdy and Strzok also became heated.

Strzok claimed Gowdy had twisted his words upon answering a question about Mueller’s decision to remove him from the team overseeing the probe into Russian influence in the 2016 presidential race, stating that he did not “appreciate” what he originally said being “changed.”

"I don’t give a damn what you appreciate, Agent Strozk," Gowdy replied. “I don't appreciate having an FBI agent with an unprecedented level of animus working on two major investigations during 2016.”

Strzok and former FBI lawyer Lisa Page, with whom he was having an affair, exchanged text messages critical of President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE during the 2016 campaign.

He was also an investigator in the probe into former Secretary of State Hillary Clinton Hillary Diane Rodham ClintonDemocratic groups using Bloomberg money to launch M in Spanish language ads in Florida The Hill's Campaign Report: Presidential polls tighten weeks out from Election Day More than 50 Latino faith leaders endorse Biden MORE's private email server.

Updated at 11:54 a.m.