MSNBC host Chris Matthews delivered a fiery tirade against Attorney General William Barr over his handling of Russia-related investigations and claimed that he was trying to "destroy the FBI" in order to protect President Donald Trump.

It was confirmed yesterday that Barr appointed U.S. Attorney John Durham to review the origins of the Russia probe that was launched during the 2016 election to determine if there was improper surveillance of the Trump campaign and that Durham has already been looking into the inquiry "for weeks."

During an interview with Rep. Joaquin Castro, D-Texas, on Monday evening, Matthews slammed Barr, referring to him as the president's "hitman" who is "out to destroy the government."

"It’s an embarrassment to have an attorney general who looks like a Roy Cohn, a guy who will do anything to defend the president and now has become his hitman," Matthews said.

US ATTORNEY JOHN DURHAM HAS BEEN REVIEWING ORIGINS OF RUSSIA PROBE 'FOR WEEKS:' SOURCE

"Not only will he play defense, he’s out to destroy the government, the FBI, everything in order to cover the tracks of the president. What do you make of this guy and how can you stop Barr from doing what he’s out to do now, destroy the FBI?”

Castro agreed, calling Barr the president's "fixer" and "protector." He also claimed that Barr was launching the probe on the origins of the Russia investigation to "chill" anyone who looks into alleged wrongdoing by Trump and refuted Barr's claim that "spying" took place during the 2016 election and that it was simply an "investigation."

The segment came after Fox News reported Durham, known as a “hard-charging, bulldog” prosecutor, according to a source, will focus on the period before Nov. 7, 2016—including the use and assignments of FBI informants, as well as alleged improper issuance of Foreign Intelligence Surveillance Act (FISA) warrants. Durham was asked to help Barr to "ensure that intelligence collection activities by the U.S. Government related to the Trump 2016 Presidential Campaign were lawful and appropriate."

A source also told Fox News that Barr is working "collaboratively" on the investigation with FBI Director Chris Wray, CIA Director Gina Haspel, and Director of National Intelligence Dan Coats, and that Durham is also working directly with Justice Department Inspector General Michael Horowitz, who is currently reviewing allegations of misconduct in issuance of FISA warrants, and the role of FBI informants during the early stages of the investigation.

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Meanwhile, President Trump on Tuesday praised Barr for appointing Durham and maintained that he did not request that the attorney general do so.

"I think it's a great thing that he did it," Trump told reporters from the White House lawn Tuesday. "I am so proud of our attorney general that he's looking into it."

Durham has led numerous public corruption probes, including organized crime, government misconduct and financial fraud matters. In 1999 AG Janet Reno appointed Durham to investigate law enforcement corruption in Boston, and under AG Eric Holder Durham was selected to investigate matters relating to the destruction of videotapes by the CIA and treatment of detainees by the CIA.