An FBI agent whose anti-Trump text messages fueled suspicions of partisan bias will tell lawmakers Thursday 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," according to prepared remarks obtained by The Associated Press.

Peter Strzok, who helped lead FBI investigations into Hillary Clinton's email use and potential coordination between Russia and Donald Trump's campaign, 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 will say 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."

Republican members of the House judiciary and oversight committees were expected to grill Strzok for hours as they argue that the text messages with FBI lawyer Lisa Page color the outcome of the Clinton email investigation and undercut the FBI's ongoing investigation into Russian election interference. Trump himself has launched personal attacks against the two FBI officials, 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."

In the prepared remarks, Strzok acknowledges 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 will say.

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."

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."