Peter Strzok's first open hearing descended into shouting matches throughout the day with Republicans getting testy with the FBI agent over his anti-Trump's texts while Strzok remained defiant and Democrats rose to his defense.

The marathon 10-hour hearing was characterized by shouting matches, cross talk, threats, one lawmaker asking another if he was off his medication, and got so contentious at times that a member called it 'a new low in the United States Congress.'

There were several memorable moments, including one in the afternoon when Republican Rep. Louie Gohmert accused Strzok of wearing a 'smirk' on his face throughout the hearing and tried to shame him by bringing up the FBI agent's affair with former agent Lisa Page.

He also accused Strzok of being a liar.

'He's lying and we know he's lying and he can probably pass the polygraph,' he said of the agent.

Peter Strzok's hearing got contentious at several points throughout the day

The 10-hour hearing was characterized by shouting matches, cross talk, threats, one lawmaker asking another if he was off his medication

'I can't help but wonder when I see you looking there with a little smirk, how many times did you look so innocent in to your wife's eyes and lied to her,' Gohmert asked.

Democrats erupted into shouts at that point. 'Shame on you,' one shouted. 'This is intolerable harassment of the witness,' said another. 'Do you need your medication?' asked a third.

Strzok hit back at Gohmert's remark: 'I assure you under oath and as I spoke also during my interview a week or two ago, I have told the truth. The fact that you would accuse me otherwise and the sort of look that I would engage with and a family member that I have acknowledged hurting goes to more of a discussion of your character and what you stand for and what's going on inside you.'

Democratic Rep. Gerry Connolly called the moment 'a new low in the United States Congress.'

'I can't help but wonder when I see you looking there with a little smirk, how many times did you look so innocent in to your wife's eyes and lied to her,' Gohmert (pictured) asked

Strzok hit back at Gohmert's (pictured) remark: 'I assure you under oath and as I spoke also during my interview a week or two ago, I have told the truth'

Later in the hearing Strzok again insisted he was not lying.

GOP congressman Rep. Mark Walker, R-N.C. discussed the content of Strzok's text messages to which Strzok responded: 'I am here under oath. I am not lying. I have never lied under oath and I never will,' Strzok said.

'The insinuation - not even the insinuation, the direct comment that you somehow say I have an integrity issue is insulting. I take offense. It is incorrect.'

As the hearing came to a close on Thursday evening, Strzok tried to explain the meaning of a cryptic text he sent Page.

The message refers to an 'insurance policy,' but the context is not clear. It reads: 'I want to believe the path you threw out for consideration in Andy's office' – referring to then-FBI Deputy Director Andrew McCabe – 'that there's no way he gets elected,' – referring to Trump – 'But I'm afraid we can't take that risk. It's like an insurance policy in the unlikely event you die before you're 40.'

Trump and Republicans have suggested the 'insurance policy' comment refers to an FBI plot to prevent Trump from winning the 2016 election.

Strzok told the hearing: 'The 'insurance policy' text that has come up before – that text represented a debate on information we had received from an extraordinarily sensitive source and method.

'Some people said, 'hey, look, every poll is saying candidate Trump is likely not to win'.

'Some people said, 'as a result of that, let's not risk that source.''

Former FBI agent Lisa Page is defying a congressional subpoena and will not appear before a closed-door session of the House Judiciary Committee

As the hearing came to a close on Thursday evening, Strzok tried to explain the meaning of a cryptic text he sent Page about an 'insurance policy'

Strzok said he represented the faction of the FBI advocating to investigate possible connections between members of the Trump camp and Russians in case Trump won.

'If candidate Trump is elected, there might be people we need to be investigating that might be nominated to important national security positions. Everybody in America would want to know that. Candidate Trump would want to know that, ' Strzok said, concluding that, 'much like you probably won't die before you're 40, that's the meaning.'

The contentious moments were there from the start.

House Oversight Committee Chairman Trey Gowdy did not hold back in his criticism of Strzok and his texts, which President Donald Trump and his allies used to paint the Russian investigation as tainted.

'You are the lead investigator, you originated the investigation, you are the point of contact, you drafted the document, and here you are before you interviewed a single solitary witness saying 'F Trump,'' he said.

Strzok did not hold back either. Given time to speak, he demanded lawmakers consider his texts in the context in which they were written - during the contentious 2016 presidential campaign when Trump had gotten into a fight with a Gold Star military family who spoke at the Democratic convention.

'In terms of the texts, “we will stop it", you need to understand that was written late at night, off-the-cuff, and in response it to a series of events that included candidate Trump insulting the immigrant family of a fallen war hero,' Strzok said.

Khizr Khan, father of deceased Muslim U.S. Soldier, holds up a booklet of the US Constitution as he delivers remarks on the fourth day of the Democratic National Convention at the Wells Fargo Center, July 28, 2016 in Philadelphia

'My presumption, based on that horrible, disgusting behavior that the American population would not elect somebody demonstrating that behavior to be president of the United States. It was in no way, unequivocally, any suggestion that me, the FBI, would take any action whatsoever to improperly impact the electoral process,' he noted.

Strzok was referring to then-candidate Trump trading barbs with Gold Star father Khizr Khan, a Hillary Clinton supporter.

Pakistan-born Khizr Khan fiercely attacked Trump at the Democratic convention in July 2016, claiming if it were up to him, his son never would have served in the military.

Deputy Assistant FBI Director Peter Strzok is sworn in before a joint committee hearing of the House Judiciary and Oversight and Government Reform committees

Peter Strzok consults with an adviser during the hearing

The agent went on to tout the virtues of the FBI and said the multiple layers of supervisors and staff would not have tolerated any signs of biased behavior from him.

'That is who we are as the FBI. And the suggestion that I in some dark chamber somewhere in the FBI would somehow cast aside all of these procedures, all of these safeguards, and somehow be able to do this is astounding to me. It simply couldn't happen. And the proposition that that is going on, that it might occur anywhere in the FBI, deeply corrodes what the FBI is in American society,' Strzok said.

Applause was heard when he finished his remarks.

Early on, a procedural fight broke out as Republicans threatened to hold Strzok in contempt for not answering their questions while Democrats attempted to adjourn the proceedings.

Civility did not rule as the day went on.

Chaos reigned on and off throughout the proceedings with Republicans attempting to get details of the Russian investigation and Democrats using every parliamentary weapon in their arsenal to disrupt proceedings.

The first 90 minutes of the hearing saw only one lawmaker get to question Strzok. And, at two and half hours into the hearing, 72 members still had to question the FBI agent. Only four members had gotten to speak to him at that point. The hearing was a joint session of the House judiciary and oversight committees, which meant an unusually large number of lawmakers were scheduled to get questioning time.

But the political firestorm started with the first question of the day.

Gowdy asked Strzok about his August 8, 2016 text exchange with his then-lover, fellow FBI agent Lisa Page, where Strzok reassured Page that she needn't worry about Donald Trump winning the White House.

The Republican lawmaker asked how many interviews Strzok, who was working on the investigation into Hillary Clinton's email server and examining Russia's role in the election, had conducted at that point to make such an allegation.

Strzok checked with the lawyers sitting behind him and then answered that the counsel of the FBI 'have directed me not to answer any questions about the ongoing investigation of the Russia.'

Republican Rep. Bob Goodlatte, who was chairing the hearing, responded that 'your testimony is essential to this hearing' and says the subpoena compels him to answer.

'I am specifically directing you to answer the question in response to our subpoena,' Goodlatte, the chairman of House Judiciary Committee, demanded.

'You at risk for a contempt citation,' he warned Strzok.

And that threat set off a firestorm of fighting and shouting among Republican and Democrats. Republicans wanted to hold Strzok in contempt while Democrats ferociously defended him and tried to end the hearing.

Several Democrats started to demand a point order and when Goodlatte refused to hear them, the lawmakers began to quibble on what is a point of order.

'The gentleman has not cited a rule of he House that is being violated so therefore it is not a point of order,' Goodlatte said in response to Democratic Rep. Jerry Nadler's demand for clarification.

At that point, Nadler made the motion to adjourn the hearing.

Chairman of the Oversight and Government Reform Committee Rep. Trey Gowdy, left, speaks with the ranking member of the committee Rep. Elijah Cummings during a hearing with FBI Deputy Assistant Director Peter Strzok

Rep. Elijah Cummings speaks as posters of those who have plead guilty to charges stemming from the Russia investigation are displayed

'The gentleman is not recognized,' Goodlatte snapped. He then demanded again that Strzok answer Gowdy's question.

'Counsel with the FBI is sitting behind me, may I consult with them?' Strzok said.

'Only with your own counsel,' Goodlatte replied.

'So I can't talk to FBI counsel?' Strzok asked.

'Only our own counsel,' Goodlatte replied.

Strzok turned around to talk to a man seated behind him and then responded: 'My counsel has reiterated that counsel for the FBI has said I cannot answer that question.'

Goodlatte told him he was at risk for contempt citation. 'You will be subject to recall to allow the committee to consider a contempt citation,' he said.

But the disagreement, which took almost an hour of the committee's time, was resolved later Thursday afternoon when Strzok and lawmakers returned from a break.

Strzok was given permission by the FBI during the break to an answer the question about how many interviews were conducted between July 31 and August 8 and did so: 'I don't recall and I'd have to check the case file.'

Gowdy responded: 'We waited all the time for that answer.'

'Yes sir,' Strzok replied and said he could not give an accurate number without a chance to check the case file.

'I know interviews were conducted. I don't know where they fell on the calendar,' he said, noting he hadn't looked at the file in at least a year.

The Republican congressman from South Carolina also asked the FBI agent why he was dismissed from special counsel Robert Mueller's team, asking if it was because he was biased in his views.

Strzok argued the Department of Justice's Inspector General report cleared him of bias as it found there was no political motivation.

'It is not my understanding that [Mueller] kicked me off because of any bias, that it was was done on the appearance,' Strzok said. 'If you want to represent what you said accurately, I am happy to answer that question, but I don't appreciate what was originally said being changed.'

'I don't give a damn what you appreciate, Agent Strzok,' Gowdy responded. 'I don't appreciate having an FBI agent with an unprecedented level of animus working on two major investigations.'

Chairman of the House Judiciary Committee Rep. Bob Goodlatte questions FBI Deputy Assistant Director Peter Strzok

FBI Deputy Assistant Director Peter Strzok testified before two House Committees in a joint session

Several Republicans used their five minutes of questioning time to make statements criticizing Strzok.

Representative John Ratcliffee hammered Strzok for using FBI phone to send anti-Trump texts and argued he left personal opinion at the door. 'Agent Strzok, are you starting to understand why some folks out there don't believe a word you say?' he said.

And Goodlatte wanted to know if Strzok would allow lawmakers to look at texts on his personal phone.

'I would authorize the release of any work related texts that are out there,' Strzok said. 'I would never agree to the release of any non-work related texts.'

Democratic lawmakers, in the meanwhile, used their time to ask for investigation into Trump's immigration policy or to defend Strzok.

Democratic Rep. Steve Cohen told Strzok that 'if I could give you a purple heart I would,' which led to some snickers from Republicans.

And Democratic Rep. Hank Johnson asked the agent: 'You used your career to keep America safe?'

'It's my proudest moment sir,' Strzok said.

Strzok laid down the gauntlet from the start of the hearing, saying in his opening statement that his work has never been tainted by politics and that the intense scrutiny he is facing represents 'just another victory notch in Putin's belt.'

Strzok was testifying publicly for the first time since being removed from special counsel Robert Mueller's team following the discovery of the derogatory text messages last year. He was also a member of the Russia investigation.

He said in his opening statement that he has never allowed personal opinions to infect his work, that he knew information during the campaign that had the potential to damage Trump but never contemplated leaking it and that the focus on him by Congress is misguided and plays into 'our enemies' campaign to tear America apart.'

But he also acknowledged the high tempers and tension that characterized the day.

'I would absolutely agree with you that there are things that I regret in retrospect and I hope that comes across today. I know a large portion of today have been combative,' he said.

Peter Strzok, the FBI agent facing criticism following a series of anti-Trump text messages, walks to gives a deposition before the House Judiciary Committee on Capitol Hill in June

President Trump has been critical of Strzok and former FBI agent Lisa Page

Trump himself has launched personal attacks against Strzok and Page, including a Wednesday evening tweet that asked 'how can the Rigged Witch Hunt proceed when it was started, influenced and worked on, for an extended period of time' by Strzok. He described the texts as 'hate filled and biased.'

Strzok acknowledged that while his text message criticism was 'blunt,' it was not directed at one person or political party and included jabs not only at Trump but also at Clinton as well as Sen. Bernie Sanders. He said there was 'simply no evidence of bias in my professional actions.'

'Let me be clear, unequivocally and under oath: not once in my 26 years of defending my nation did my personal opinions impact any official action I took,' he said.

He says that he was one of the few people during the 2016 election who knew the details of Russian election interference and its possible connections with people in the Trump orbit, and that that information could have derailed Trump's election chances. 'But,' he said, 'the thought of exposing that information never crossed my mind.'

Although Strzok has said through his lawyer that he was eager to tell his side of the story, he makes clear his exasperation at being the focal point of a congressional hearing at a time when Russian election interference has been successfully 'sowing discord in our nation and shaking faith in our institutions.'

'I have the utmost respect for Congress's oversight role, but I truly believe that today's hearing is just another victory notch in Putin's belt and another milestone in our enemies' campaign to tear America apart,' Strzok says. 'As someone who loves this country and cherishes its ideals, it is profoundly painful to watch and even worse to play a part in.'

Strzok says 'I have the utmost respect for Congress's oversight role, but I truly believe that today's hearing is just another victory notch in Putin's belt'

Strzok says the Russian investigation is 'not a witch hunt'

He also flatly rejected the president's characterizations of Mueller's work and the threat of Russian election interference, saying, 'This investigation is not politically motivated, it is not a witch hunt, it is not a hoax.'

The Justice Department's inspector general has criticized Strzok and Page for creating the appearance of impropriety through the texts. But the report said it found no evidence of political bias in the FBI's decision to not pursue criminal charges against Clinton. And many Democrats say actions taken by law enforcement during the campaign season - including announcing a reopening of the investigation into Clinton just days before the election - actually wound up harming the Democratic candidate and aiding the Republican candidate, Trump.

FBI Director Chris Wray says the FBI has referred to internal disciplinary officials employees who were singled out for criticism in the inspector general's report. Strzok's lawyer has said he was escorted from the FBI building last month as the disciplinary process winds its way through the system.

Page left the bureau in May. She will appear before the committees in a closed session on Friday that is expected to go into Monday.

As the hearing finished, the ranking Democrats on the Judiciary and Oversight Committees, Rep. Elijah Cummings, D-Md., and Rep. Jerry Nadler, D-N.Y., released a statement calling Thursday's partisan spectacle 'a giant love letter to President Trump'.