FBI Director James Comey requested additional money and manpower from Deputy Attorney General Rod Rosenstein for the investigation into Russian interference in the presidential election just days prior to his firing, according to a U.S. official with knowledge of the situation.

The request, first reported by The New York Times, comes as Trump administration officials claim that Comey's termination is unrelated to the investigation. Comey additionally briefed some members of the Senate Intelligence Committee on the request on Monday.

A spokesperson from the Justice Department explicitly denied that such a request was made, saying it is "100 percent false" and that "it didn't happen."

The spokesperson added that the denial came directly from Rosenstein himself, who authored a letter to Trump Tuesday recommending Comey's dismissal.

The nation's capital was thrust into political turmoil on Tuesday with the unexpected firing. Rosenstein's letter made the case that Comey be removed because senior Justice Department administration officials believed he had unfairly treated Hillary Clinton in last year's investigation of her emails and damaged the credibility of the bureau and the Justice Department as a result.

But the timing of the announcement shocked politicians on both sides of the political aisle in part due to the ongoing FBI investigation into possible contacts between Russia and Trump associates during the run-up to the 2016 election and after, which Comey was leading.

Trump administration's rationale

According to the White House, Comey lost his job because of his handling of the FBI's investigation of Hillary Clinton's emails.

"I have received the attached letters from the Attorney General and Deputy Attorney General of the United States recommending your dismissal as the Director of the Federal Bureau of Investigation," wrote President Trump in letter to Comey on Tuesday, informing him of the move. "I have accepted their recommendation and you are hereby terminated and removed from office, effective immediately."

Attorney General Jeff Sessions' letter to the president was also released, wherein he stated that he had "concluded that a fresh start is needed at the leadership of the FBI."

"It is essential that this Department of Justice clearly reaffirm its commitment to longstanding principles that ensure the integrity and fairness of federal investigations and prosecutions. The Director of the FBI must be someone who follows faithfully the rules and principles of the Department of Justice and who sets the right example for our law enforcement officials and others in the Department," Sessions wrote.

The letter from Deputy Attorney General Rod Rosenstein credited Comey with being "an articulate and persuasive public speaker about leadership" but went on to note that he "cannot defend the Director's handling of the conclusion of the investigation of Secretary Clinton's emails, and I do not understand his refusal to accept the nearly universal judgment that he was mistaken."

"Almost everyone agrees that the Director made serious mistakes; it is one the few issues that unites people of diverse perspectives," Rosenstein wrote.

The letter goes on to allege that Comey was wrong to later "hold press conferences to release derogatory information about the subject of a declined criminal investigation."

Typically when the FBI decides not to bring charges against someone, it normally does not discuss its decision-making. When Comey held a July 5 news conference explaining why Clinton would not be facing charges but at the same time criticizing her email practices, he cited "intense public interest" as the reason for the exception.

Trump praised Comey last October, saying "it took guts" for Comey to announce that the FBI would be reviewing emails in the previously closed investigation into Clinton's private email server.

Russia investigation

Despite the Trump's administration's rationale for Comey's firing, talk around Washington swirled about the timing given the ongoing FBI investigation into possible Russian contacts with Trump associates.

Sen. Chuck Schumer, D-N.Y., said at a press conference Tuesday evening that he told President Trump firing Comey was a "big mistake," because it raises suspicions about whether the Trump administration is trying to purge the Justice Department of the top officials investigating Russia's interference in the 2016 election.

"This is part of a troubling pattern from the Trump administration. They fired Sally Yates. They fired Preet Bharara. And now they fired director Comey, the very man leading the investigation. This does not seem to be a coincidence," he said, adding that there should be a special prosecutor to investigate Russia because it is the "only way to restore the American people's faith."

While testifying in front of the House Committee on Intelligence on March 20, 2017, Comey took the rare step of confirming the FBI was investigating Russian interference in the U.S. election and "any links between individuals associated with the Trump campaign and the Russian government and whether there was any coordination between the campaign and Russia's efforts."

In Trump's letter to Comey on Tuesday, he seemed to reference that probe.

"While I greatly appreciate you informing me, on three separate occasions, that I am not under investigation, I nevertheless concur the judgment of the Department of Justice that you are not able to effectively lead the Bureau."

Others also expressed befuddlement that Attorney General Sessions appeared to have a say in the decision to remove Comey, since Sessions had earlier recused himself from overseeing an investigation into possible Russian contacts with Trump associates after himself failing to disclose meetings he had with Russia's ambassador to the U.S., Sergey Kislyak.

"AG Sessions lied under oath about meetings with Kislyak," tweeted Sen. Kirsten Gillibrand, D-N.Y. "One way to exert control after recusal is by getting rid of FBI Director. Chilling."

Republicans were generally more muted in their reaction to Comey's firing, with some supporting the decision.

But a number nonetheless joined their Democratic colleagues in questioning the decision or the timing.

Sen. Ben Sasse, R-Neb., the chairman of the Judiciary Committee's Oversight Subcommittee, said the timing was "troubling."

"Regardless of how you think Director Comey handled the unprecedented complexities of the 2016 election cycle, the timing of this firing is very troubling," his statement from Tuesday night read.

Sen. John McCain, R-Ariz., said the firing, while within the president's authority, showed the need for an independent committee to lead the Russian investigations.

"I have long called for a special congressional committee to investigate Russia's interference in the 2016 election," he said in a statement Tuesday evening. "The president's decision to remove the FBI Director only confirms the need and the urgency of such a committee."

Rep. Justin Amash, R-Mich., said he and his staff were "reviewing legislation to establish an independent commission on Russia," calling the part of Trump's letter to Comey "bizarre" where the president expressed appreciation for Comey allegedly saying he wasn't under investigation.