Former Deputy Attorney General Rod Rosenstein Rod RosensteinDOJ kept investigators from completing probe of Trump ties to Russia: report Five takeaways from final Senate Intel Russia report FBI officials hid copies of Russia probe documents fearing Trump interference: book MORE offered a vigorous defense of his decisions in the Justice Department on Monday evening, including his role in President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE’s sudden firing of James Comey James Brien ComeyDemocrats fear Russia interference could spoil bid to retake Senate Book: FBI sex crimes investigator helped trigger October 2016 public probe of Clinton emails Trump jabs at FBI director over testimony on Russia, antifa MORE as FBI director, whom he said has become "a partisan pundit" since his ouster.

Rosenstein, in a speech before the Greater Baltimore Committee's (GBC) annual meeting, described the firing as a difficult judgment call that was made after Comey strayed from the long-standing practices the FBI and the Department of Justice (DOJ) adhere to when dealing with open investigations.

The recently retired DOJ official also defended his oversight of the counterintelligence investigation into whether members of the Trump campaign conspired with Russia to win the 2016 election amid criticism that Comey’s firing was an attempt to obstruct the probe, which was ultimately completed by special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE. ADVERTISEMENT

"I would never have allowed anyone to interfere with the investigation," Rosenstein told the GBC, according to prepared remarks.

The White House initially pinned the decision to fire Comey on Rosenstein’s May 9, 2017, memo, a three-page document that transformed the former deputy attorney general from a little-known Justice Department official to one of the most scrutinized officials in the Russia probe. Trump later told NBC News’s Lester Holt that the Russia investigation factored into his thinking and that he would have fired Comey "regardless of recommendation."

Mueller investigated Comey’s firing among roughly a dozen episodes of possible obstruction of justice by Trump. The special counsel ultimately did not reach a conclusion on whether Trump obstructed the probe, writing in his report that his investigators could not "conclusively" determine Trump did not commit a crime.

Rosenstein said Monday that no one told him that Comey’s ouster "was intended to influence the course" of the Justice Department’s investigation into Russia's interference.

"The special counsel’s report states that the president’s counsel advised me on a Monday afternoon that the president had decided to remove the director," Rosenstein said. "It was news to me. Nobody said that the removal was intended to influence the course of my Russia investigation."

Rosenstein pointed to Comey’s unprecedented decisions surrounding the FBI’s investigation into Hillary Clinton Hillary Diane Rodham ClintonDemocratic groups using Bloomberg money to launch M in Spanish language ads in Florida The Hill's Campaign Report: Presidential polls tighten weeks out from Election Day More than 50 Latino faith leaders endorse Biden MORE’s handling of classified materials while secretary of State as the basis for his firing, stating that his actions "were not within the range of reasonable decisions."

Those actions include his decision to announce in July 2016 — without the consent of DOJ prosecutors or former Attorney General Loretta Lynch — that the FBI investigation had closed the Clinton email probe and that the bureau was not recommending criminal charges against Clinton as well as his subsequent decision to announce just days before the polls opened in 2016 that the bureau was reopening its investigation into Clinton's emails after additional records had been recovered.

"They were inconsistent with our goal of communicating to all FBI employees that they should respect the Attorney General’s role, refrain from disclosing information about criminal investigations, avoid disparaging uncharged persons, and above all, not take unnecessary steps that could influence an election," Rosenstein said.

According to Rosenstein’s account, the president shared a letter laying out his reasons for firing Comey before asking the No. 2 DOJ official to give then-Attorney General Jeff Sessions Jefferson (Jeff) Beauregard SessionsGOP set to release controversial Biden report Trump's policies on refugees are as simple as ABCs Ocasio-Cortez, Velázquez call for convention to decide Puerto Rico status MORE a memo outlining his concerns about Comey’s conduct the following morning.

Rosenstein, who left the Justice Department last week, noted that those who serve as the head of the FBI are often required to make tough choices. But he added that Comey, rather than reflecting on his mistakes, made it clear he stood by his decisions while testifying before Congress.

"In essence, he said that he would do it again if he had the chance," Rosenstein said.

Rosenstein said he would’ve handled the firing differently, but he defended the reasons he laid out in his memo.

"If I had been asked to make a recommendation before the removal decision was made, I would have included a more balanced analysis of the pros and cons. But my brief memo to the Attorney General is correct, and it was reasonable under the circumstances," Rosenstein said.

"If I had been the decision-maker, the removal would have been handled very differently, with far more respect and far less drama," he continued.

Rosenstein said he personally "admired" Comey for his leadership of the FBI and he did not "blame" him for being angry over his termination, but he also blasted the former director for since becoming "a partisan pundit" who has repeatedly attacked his character.

"Now the former Director is a partisan pundit, selling books and earning speaking fees while speculating about the strength of my character and the fate of my immortal soul," Rosenstein said. "That is disappointing. Speculating about souls is not a job for police and prosecutors. Generally we base our opinions on eyewitness testimony."

Rosenstein also defended his decision to appoint a special counsel to oversee the case, deeming that such a move would "best protect America from foreign adversaries and preserve public confidence in the long run."

"I knew that some people would not be happy about it. I knew that it would be unpleasant for me and my family. But at my confirmation hearing, I promised that I would conduct the investigation properly and see it through to the appropriate conclusion," Rosenstein said. "In my business, you keep promises. And in my business, the appropriate conclusion is the one that results when you follow the normal process and complete an independent investigation," he continued.

The appearance represented Rosenstein’s second public remarks as a private citizen since departing the Trump administration just two days ago. Hours earlier, Rosenstein delivered a commencement address at the University of Baltimore School of Law, during which he quoted Mueller in advising students to not succumb to pressure to abandon their principles.

Morgan Chalfant contributed.