An already raucous hours-long Congressional hearing into FBI agent Peter Strzok's apparent anti-Trump bias boiled over on Thursday afternoon, as a top Republican asked the "smirking" Strzok whether he was lying under oath the same way he "lied" to his wife while he carried on an affair with now-former FBI lawyer Lisa Page.

"The disgrace is what this man has done to our justice system," Rep. Louie Gohmert, R-Texas, shouted over objections by Democrats. "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 eyes and lie to her about Lisa Page?"

Democrats immediately erupted into more objections, with one yelling, "Mr. Chairman, this is intolerable harassment of the witness" and another calling out, "You need your medication."

Strzok and Page exchanged numerous text messages on their FBI-issued phones expressing hostility toward then-candidate Trump in the run-up to the 2016 presidential election, even as Strzok was a lead investigator on the Hillary Clinton and Russian meddling probes.

The two also communicated on their work phones to hide their affair from their spouses, according to a bombshell report released last month by the Justice Department's inspector general.

FBI LOVEBIRDS USED WORK PHONES TO HIDE AFFAIR, IG FINDS

Page had been expected to testify Wednesday in a closed-door session, but backed out at the last minute, saying she needed more time to prepare. She is now expected to interview privately on Friday with GOP leaders.

Gohmert's question was just one of several tense moments in the hearing, the Republicans' first opportunity to question the embattled FBI agent publicly. Democrats frequently interrupted the proceedings during questioning by GOP representatives.

A senior House Republican told Fox News that the hearing has been a "disaster for both sides," saying that Strzok has come out looking better than the bitterly feuding Democrats and Republicans in the House.

At one point, Republicans threatened Strzok with contempt for initially refusing to answer questions on the Russia probe.

Strzok, throughout it all, remained defiant and maintained that he did not show bias in those infamous messages with Page -- saying that while he had his own political opinions, they did not impact his official investigative actions.

Strzok did express "significant regret" for the problems caused by his frequent anti-Trump texts, and described his use of an FBI-issued phone to discuss politics as an instance of "bad judgment" that has tarnished the image of the FBI.

However, Strzok stated that he maintains a top secret security clearance, despite Attorney General Jeff Sessions earlier saying that he believed Strzok's security credentials had been revoked.

Strzok confirmed under questioning by Rep. Gary Palmer, R-Ala., that he was being investigated by the FBI's Office of Professional Responsibility (OPR), but was not aware of whether the DOJ watchdog also was reviewing his conduct. OPR previously reviewed former FBI Deputy Director Andrew McCabe's performance and recommended his termination.

But earlier in the hearing, Strzok had told Rep. Darrell Issa, R-Calif., "I am not aware of any investigation of which I am a target."

FIREWORKS AT STRZOK HEARING, AS GOP LEADERS THREATEN CONTEMPT

“I don’t give a damn what you appreciate, Agent Strzok." — Rep. Trey Gowdy, R-S.C.

The initial contempt threat surfaced after House Oversight Committee Chairman Trey Gowdy, R-S.C., questioned "how many witnesses" Strzok interviewed before an August 2016 text from Strzok to Page stating "we'll stop" then-candidate Trump from becoming president.

Strzok said he was not able to answer the question based on instructions from FBI counsel. House Judiciary Committee Chairman Bob Goodlatte, R-Va., rejected Strzok's claim.

"Mr. Strzok, you are under subpoena and required to answer the question," Goodlatte said.

This touched off a heated dispute. Judiciary Ranking Member Jerry Nadler, D-N.Y., blasted Goodlatte for putting Strzok in an "impossible position," while Strzok claimed he was there voluntarily. Goodlatte said Strzok could consult only with his own attorney, not the FBI's.

Several other committee members chimed in, blasting top Republicans on the committee, with Nadler even motioning to adjourn the hearing all together.

Gowdy also tore into Strzok at the opening of Thursday's hearing, saying he showed "textbook bias" on the job. The rhetoric later escalated into a heated exchange in which Strzok claimed he was kicked off Special Counsel Robert Mueller's probe because of "perception," not because of bias.

After Strzok said he didn't "appreciate" how Gowdy was characterizing those events, the congressman fired back: “I don’t give a damn what you appreciate, Agent Strzok.”

Under questioning by Rep. Matt Gaetz, R-Fla., Strzok later admitted that Mueller never explicitly told him why he was kicked off the Russia probe -- and that Mueller never asked him whether he had any biases that might affect the investigation.

"I think he didn’t ask because he didn’t want to know the answer of whether you were biased," Gaetz charged.

There were moments for Congressional Democrats to lend some support for Strzok, beyond objecting to Republican questions. Rep. Steve Cohen, D-Tenn., even suggested that Strzok, a former Army officer, deserved a Purple Heart because of the fierce Republican criticism.

'If I could give you a Purple Heart, I would," Cohen said. The Purple Heart is awarded to wounded or killed soldiers.

Fox News' Brooke Singman, Chad Pergram, and Jenny Buchholz contributed to this report.