Robert Mueller
Robert Mueller Reuters

The Justice Department on Wednesday appointed former FBI Director Robert Mueller as special counsel to oversee the federal investigation into alleged Russian interference in the 2016 election.

Deputy Attorney General Rod Rosenstein appointed Mueller to the position in a letter obtained by CNN.

Attorney General Jeff Sessions previously recused himself from any involvement in the Russia investigation due to his role as a prominent campaign adviser and surrogate.

Mueller will be "authorized to prosecute federal crimes arising from the investigation of these matters," read the Justice Department order Rosenstein signed.

"In my capacity as acting attorney general, I determined that it is in the public interest for me to exercise my authority and appoint a Special Counsel to assume responsibility for this matter," Rosenstein said in a statement quoted by CNN, adding that the decision is "not a finding that crimes have been committed or that any prosecution is warranted."

"What I have determined is that based upon the unique circumstances, the public interest requires me to place this investigation under the authority of a person who exercises a degree of independence from the normal chain of command," Rosenstein added.

Rosenstein said he believes a special counsel "is necessary in order for the American people to have full confidence in the outcome."

Mueller's appointment aims to quell the wave of criticism that President Donald Trump and his administration have faced since Trump fired FBI Director James Comey last week in the middle of the FBI's investigation into contacts between Trump campaign associates and Russian officials.

That criticism swelled on Tuesday evening as excerpts of a memo Comey wrote in February surfaced, in which Comey writes Trump asked him to drop the FBI investigation into former national security adviser Michael Flynn.

Trump asked for Flynn’s resignation in February, after it was revealed that he misled Vice President Mike Pence about his conversations with the Russian Ambassador to the U.S., which included discussions about U.S. sanctions on Russia.

While Trump has accepted intelligence reports concluding that Russia engaged in cyber attacks during the November presidential election, he has repeatedly lambasted as “fake news” any suggestion that he or his staff had connections to Russia.

Russia denies the allegations altogether.

Responding on Wednesday night to the appointment of Mueller, Trump said that the probe would show there was no collusion between his campaign and Russia.

"As I have stated many times, a thorough investigation will confirm what we already know –- there was no collusion between my campaign and any foreign entity," he said in a statement released by the White House.

"I look forward to this matter concluding quickly. In the meantime, I will never stop fighting for the people and the issues that matter most to the future of our country," added Trump.

Mueller was appointed FBI Director by President George W. Bush in 2001 and served until 2013, when Comey took over as head. He will resign from his private law firm to avoid any conflicts of interest, the Justice Department said, according to CNN.