The White House lashed out against “disgraced partisan hack” James Comey and “known liar” Andrew McCabe on Friday after a report that the FBI -- after President Trump fired Comey as the bureau's director -- opened a secret inquiry into whether Trump had been working on behalf of Russia against American interests.

The investigators working on the inquiry had to assess whether Trump’s actions could constitute a possible national security threat. The agency tried to determine whether the president was working for Russia or had fallen under the Kremlin’s influence, the New York Times reported.

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The probe into Trump also looked into possible criminality, in particular the May 2017 firing of Comey and whether that could be deemed an obstruction of justice.

But the timing of the investigation raises questions as both Comey and FBI lawyer Lisa Page told House investigators last year that by the time the FBI director was fired and special counsel appointed, there was no hard evidence of collusion between the Trump campaign and the Kremlin.

“In fact, when I was fired as director, I still didn't know whether there was anything to it,” Comey said in a recent testimony, according to the transcript.

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Trump fired back on early Saturday morning, slamming "the corrupt former leaders of the FBI" for opening an investigation on him after firing "total sleaze" Comey.

"Wow, just learned in the Failing New York Times that the corrupt former leaders of the FBI, almost all fired or forced to leave the agency for some very bad reasons, opened up an investigation on me, for no reason & with no proof, after I fired Lyin’ James Comey, a total sleaze!" he wrote in a tweet.

"Funny thing about James Comey. Everybody wanted him fired, Republican and Democrat alike. After the rigged & botched Crooked Hillary investigation, where she was interviewed on July 4th Weekend, not recorded or sworn in, and where she said she didn’t know anything (a lie)," Trump continued, adding that "my firing of James Comey was a great day for America. He was a Crooked Cop."

The White House also pushed back against the report on Friday, calling the insinuations of working for Russia “absurd” and pointed to the administration's record toward Russia.

"This is absurd. James Comey was fired because he's a disgraced partisan hack, and his Deputy Andrew McCabe, who was in charge at the time, is a known liar fired by the FBI." — White House press secretary Sarah Sanders

“This is absurd. James Comey was fired because he's a disgraced partisan hack, and his Deputy Andrew McCabe, who was in charge at the time, is a known liar fired by the FBI,” White House press secretary Sarah Sanders said in a statement.

“Unlike President Obama, who let Russia and other foreign adversaries push American around, President Trump has actually been tough on Russia,” she added.

John Dowd, the president's attorney on special counsel matters, said that “at no time did Special Counsel Mueller make requests of the president or his counsel about these bizarre allegations."

"The NY Times story is an unwitting disclosure and verification of the utter corruption of their oaths by Comey and his colleagues to undermine the free election of the President of the United States. It was apparently done under the supervision of the Deputy Attorney General who was reportedly ready to wear a wire to ensnare President Trump. This is the stuff of banana republics and dictatorships," the statement said. "This despicable, unlawful, official conduct undermines our entire federal criminal justice system which protects our liberty as a free people.”

Rep. Devin Nunes, R-Calif., the ranking member of the House Intelligence Committee, said the story was "more evidence that FBI leaders actually had no real evidence against the Trump team."

"Instead, they were simply trying to undermine a president they didn’t like and avenge Comey’s firing. By relying on the Steele dossier—a fraudulent document funded by Democrats and based on Russian sources -- FBI leaders were either complicit or too oblivious to notice they were being used in a disinformation operation by the Democratic Party and Russian operatives,” he said in a statement.

Comey didn't directly respond on the story or Trump's remarks, only tweeting a quote from former President Franklin D. Roosevelt: "I ask you to judge me by the enemies I have made.”

The allegation of the FBI opening a counterintelligence investigation into Trump may cause a further rift between the bureau and the president, who in the past has criticized the agency’s senior leadership, alleging an anti-Trump bias.

Among those FBI officials accused of bias were former senior counterintelligence agent Peter Strzok, who was fired amid revelations of his anti-Trump and pro-Hillary Clinton text messages with another FBI official, Lisa Page.

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McCabe, a former FBI deputy director, meanwhile, was fired in March ahead of his planned retirement following a bombshell report by Justice Department Inspector General Michael E. Horowitz that claimed McCabe lied to investigators and his then-boss Comey at least four times, three of them under oath.

The former deputy director reportedly authorized a leak to a newspaper reporter about the contents of a telephone call on August 2016 in order cast himself in a positive light in an upcoming story about an investigation involving Hillary Clinton.

According to the Times, senior FBI officials became suspicious of Trump and his alleged ties to Russia during the 2016 presidential campaign but decided not to pursue an investigation at the time. The president’s decisions and the firing of Comey prompted the agency to launch the inquiry.

The FBI investigation has since been taken over by Special Counsel Robert Mueller, who is examining the possibility of collusion between the Trump campaign and Russia. There’s no indication that Mueller is continuing to pursue the counterintelligence matter.

Former law enforcement officials told the newspaper that the criminal and counterintelligence elements of the investigation were combined because Trump’s firing of the FBI director could constitute both a crime and a national security threat as it would hinder the agency’s abilities to learn how the Kremlin interfered in the 2016 election.

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“Not only would it be an issue of obstructing an investigation, but the obstruction itself would hurt our ability to figure out what the Russians had done, and that is what would be the threat to national security,” James A. Baker, who served as FBI general counsel until late 2017, said during private testimony before House investigators in October, according to the Times.

Fox News' Catherine Herridge contributed to this report.