WASHINGTON — The embattled F.B.I. agent who oversaw the opening of the Russia investigation mounted an aggressive personal defense on Thursday, rejecting accusations that he let his private political views bias his official actions and labeling Republican attacks on him “another victory notch in Putin’s belt.”
“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,” the agent, Peter Strzok, was to tell House lawmakers investigating what they say is evidence of rampant bias at the top levels of the F.B.I.
In his first public comments, he concluded his prepared remarks with a pointed broadside against his antagonizers.
“I understand we are living in a political era in which insults and insinuation often drown out honesty and integrity,” Mr. Strzok planned to say, continuing: “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 concluded: “As someone who loves this country and cherishes its ideals, it is profoundly painful to watch and even worse to play a part in.”
Mr. Strzok, a career agent, played a pivotal role in two of the bureau’s most politically fraught cases: the F.B.I.’s investigation into Hillary Clinton’s email practices as secretary of state and a separate inquiry into Russia’s attempts to interfere in the 2016 election and its interactions with the Trump campaign.
Mr. Strzok has come under intense scrutiny since the Justice Department’s inspector general discovered thousands of text messages that he exchanged with a senior F.B.I. lawyer, Lisa Page, working on both investigations colorfully disparaging Mr. Trump.
In one exchange, Ms. Page said to Mr. Strzok, Trump is “not ever going to become president, right?”
“No. No he won’t. We’ll stop it,” Mr. Strzok replied.
House Republicans and Mr. Trump have seized on those texts, charging that they undercut the integrity of the Russia investigation, which has since been taken over by the special counsel, Robert S. Mueller III. Republican lawmakers were prepared to confront the former agent with volumes of such messages on Thursday.
Mr. Strzok said he deeply regretted the messages, but he said that they did not amount to more than private political beliefs.
“In the summer of 2016, we had an urgent need to protect the integrity of an American Presidential election from a hostile foreign power determined to weaken and divide the United States of America,” he said. “This investigation is not politically motivated, it is not a witch hunt, it is not a hoax.”
The inspector general’s report was unsparing in its criticism of Mr. Strzok and Ms. Page, but found no evidence that their personal views had affected prosecutorial decisions in the Clinton case. The inspector general, Michael E. Horowitz, continues to investigate the F.B.I.’s handling of key aspects of the Russia case.
Mr. Strzok, who spent a contentious day locked behind closed doors for an interview with the same lawmakers late last month, did not have kind words for the Republicans leading the committee.