F.B.I. Agent at Center of Russia Probe Turns Tables on G.O.P.

WASHINGTON — The embattled F.B.I. agent who oversaw the opening of the Russia investigation mounted an aggressive personal defense on Thursday, rejecting accusations in which he let his private political views bias his official actions as well as labeling Republican attacks on him “another victory notch in Putin’s belt.”

“Let me be clear, unequivocally as well as 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 will be evidence of rampant bias at the top levels of the F.B.I.

In his first public comments, he concluded his prepared remarks using a pointed broadside against his antagonizers.

“I understand we are living in a political era in which insults as well as insinuation often drown out honesty as well as integrity,” Mr. Strzok planned to say, continuing: “I possess the utmost respect for Congress’s oversight role, although I truly believe in which today’s hearing will be just another victory notch in Putin’s belt as well as another milestone in our enemies’ campaign to tear America apart.”

He concluded: “As someone who loves This particular country as well as cherishes its ideals, the item will be profoundly painful to watch as well as 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 as well as a separate inquiry into Russia’s attempts to interfere from the 2016 election as well as 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 in which he exchanged using a senior F.B.I. lawyer, Lisa Page, colorfully disparaging Mr. Trump.

In one exchange, Ms. Page, who also worked on both investigations, said to Mr. Strzok, Trump will be “not ever going to become president, right?”

“No. No he won’t. We’ll stop the item,” Mr. Strzok replied.

House Republicans as well as Mr. Trump have seized on those texts, charging in which 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 in which he deeply regretted the messages, although in which they did not amount to more than private political beliefs.

“from the summer of 2016, we had an urgent need to protect the integrity of an American presidential election through a hostile foreign power determined to weaken as well as divide the United States of America,” he was to say. “This particular investigation will be not politically motivated, the item will be not a witch hunt, the item will be not a hoax.”

The inspector general’s report was unsparing in its criticism of Mr. Strzok as well as Ms. Page, although found no evidence in which their personal views had affected prosecutorial decisions from 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.