WASHINGTON — Deepening tension between congressional Republicans and the Justice Department erupted in full public view Thursday, as a senior FBI agent sparred with lawmakers who suggested his bias against President Trump tainted the department’s Russia investigation.

Peter Strzok, the senior FBI official who oversaw the Hillary Clinton email investigation and helped lead the initial probe of ties between Russia and the Trump campaign strongly rejected claims that personal political views he shared with a colleague affected his official actions, while accusing Republicans of furthering Vladimir Putin’s goal of sowing discord in the U.S.

“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,” he said at a joint hearing of the House Oversight and Judiciary Committees, who have been jointly probing the Justice Department’s handling of both probes Strzok helped lead.

But during the course of a nearly 10-hour hearing, dozens of Republicans relentlessly questioned Strzok over some of the thousands of text messages he exchanged with Lisa Page, counsel to then-FBI deputy director Andrew McCabe, in which the two were critical of then-candidate Trump.

Rep. Trey Gowdy, R-S.C., noted that in August of 2016, within one week of the Justice Department’s decision to open the Russia probe, Page and Strzok exchanged messages that included “F Trump,” and Strzok saying: “I can protect our country at so many levels.”

“We're not even a week into an investigation that you originated, approved, were the contact for, you hadn't interviewed a single solitary soul until August the 11th, and you're already promising to protect the country from that menace Donald Trump,” Gowdy said.

Strzok repeatedly expressed regret over what he called “blunt” comments about Trump and other political figures, but refused to concede that those comments represented bias against Trump. Responding to Gowdy, Strzok said messages such as that one were “written late at night, off-the-cuff,” and reflecting his immediate views about news of the day.

“To suggest somehow we can parse down the words of short hand textual conversations like they're some contract for a car is simply not consistent with my or most people's use of text messaging,” he said. “The suggestion that I in some dark chamber somewhere in the FBI would somehow cast aside all of these procedures, all of these safe guards, and somehow be able to do this is astounding me. It simply couldn’t happen. And the proposition that it is going on, that it might occur anyway in the FBI, deeply corrodes what the FBI is in American society.”

Strzok noted that he was one of a very small number of people with knowledge of the fact that the FBI had launched a counterintelligence investigation involving the Trump campaign.

“This information had the potential to derail, and quite possibly, defeat Mr. Trump. But the thought of exposing that information never crossed my mind,” he said.

Democrats largely used the hearing to attack Republicans for what they described as a coordinated effort with the White House to delegitimize the Russia probe now led by special counsel Robert Mueller.

"Accountability is coming one way or another, and they are scared and are trying to undermine the investigation,” said Rep. Jerry Nadler, D-N.Y., the top Democrat on the House Judiciary Committee.

At one point the hearing devolved into a shouting match between Republicans and Democrats over procedural issues, after Strzok said he had been instructed by Justice Department not to answer a question about the Russia investigation, because it is ongoing. Republicans threatened to hold him in contempt of Congress, which Democrats contested. Rep. Zoe Lofgren, D-Calif. called it a “circus,” while Gerry Connolly, D-Va., called it a “political show trial.”

The more than 40,000 text messages exchanged between Strzok and Page, who were engaged in an extramarital affair, have been held up by Republicans as a prime example of political bias that infected the Justice Department and reflected animus against the Republican candidate. Trump has often tweeted about Strzok and Page as an example of what he has called a “witch hunt” against him.

In another example, Page wrote to Strzok in August of 2016: “[Trump’s] not ever going to become president, right? Right?!” Strzok replied: “No. No he’s not. We’ll stop it.”

Peter Strzok stares down the media before his testimony. Mark Wilson / Getty Images

House Judiciary Committee Chairman Bob Goodlatte, R-Va., who accused Strzok of “turn[ing] our system of justice on its head,” asked Strzok about another message in which he wrote he had just come from a Northern Virginia Wal-Mart and could “smell” the Trump supporters.

Strzok downplayed the comment, saying it simply was his way of expressing what he called "the extraordinary difference in the expression of political opinion and belief amongst the community there from where I live."

“You don’t think that it was the bias expressed in your text messages that caused Mr. Mueller to remove you from the investigation?” Goodlatte asked.

“I do not think that … bias was expressed in those text messages,” Strzok replied.

Rep. Louie Gohmert, R-Texas, at one point called Strzok “disgraceful,” accusing him of lying to the committee under oath and even raising his extramarital affair.

"I can’t help but wonder when I see you looking there with a little smirk, how many times did you look so innocent into your wife’s eye and lie to her,” Gohmert said, prompting howls from Democrats at what they called an “outrageous” comment.

“I have always told the truth,” Strzok replied "The fact that you would accuse me otherwise, the fact that you would question whether or not that was the sort of look I would engage with with a family member who I have acknowledged hurting goes more to a discussion of your character."

While most of the Republicans questions focused on his texts, several attempted to uncover new information about the origins of the Russia probe, and whether information from former British intelligence operative Christopher Steele, whose work was being funded by Democratic-linked firm, helped launch it.

Strzok said that an FBI official did present information in September of 2016 that included "some elements of reporting that ... originated from Mr. Steele.” But that was months after the probe began.

“The information we had which was alleging a Russian offer of assistance to a member of the Trump campaign was of extraordinary significance,” he said. “It was credible. It was from an extraordinarily sensitive and credible source.”

Strzok was removed as a member of Special Counsel Robert Mueller’s team one day after Horowitz team disclosed to him the existence of Strzok’s anti-Trump texts.

Strzok had already appeared before the same committees in June for a closed, 11-hour interview with the same congressional committees. Democrats tried unsuccessfully to force Republicans to release the transcript of that interview, which they said included many of the same questions being asked publicly Thursday.

The Strzok-Page messages were uncovered as part of an investigation by the Justice Department watchdog into how the FBI handled the Clinton email probe. In an extensive report released last month, FBI Inspector General Michael Horowitz wrote that he was “deeply troubled” by the messages, which “potentially indicated or created the appearance that investigative decisions were impacted by bias or improper considerations.”

“Although we found no documentary or testimonial evidence directly connecting the political views these employees expressed in their text messages and instant messages to the specific [Clinton email] investigative decisions we reviewed … the messages cast a cloud over the FBI investigations to which these employees were assigned,” he concluded.

Page, who initially defied a subpoena from the House Judiciary and Oversight Committees to appear for a closed interview Wednesday, is now expected to appear before lawmakers Friday.