FBI Deputy Director Andrew "Andy" McCabe will serve as the acting director of the FBI after Jim Comey was fired Tuesday by President Donald Trump.

"By operation of law and effective immediately, Deputy Director Andrew McCabe assumed the position of Acting Director of the FBI," Attorney General Jeff Sessions said in a memo to FBI employees obtained by CNN. "As you well know, the FBI is an exceptional law enforcement and intelligence agency. It is made so by you, the devoted men and women who work tirelessly to keep our coutnry safe. Thank your for your steadfast dedication and commitment during this time of transition."

McCabe was appointed to the deputy director position in January 2016 by Comey, according to a FBI press release.

"Andy's 19 years of experience, combined with his vision, judgment, and ability to communicate make him a perfect fit for this job," Comey said in a statement at the time. In the deputy role, McCabe oversees "all FBI domestic and international investigative and intelligence activities and will serve as acting director in the director's absence."

McCabe, a 49-year-old father of two from Virginia, is a controversial figure for Republicans, as questions have been raised about his involvement in the Hillary Clinton email investigation and the Russia election probe because his wife, Dr. Jane McCabe, has run for office as a Democrat and has ties to top Clinton donors and allies. Many Trump supporters on Twitter are calling for McCabe to be fired along with Comey.

A search for a new director began immediately after Comey was fired, the White House said. The new FBI director will need to receive approval from the Senate.

"The FBI is one of our Nation's most cherished and respected institutions and today will mark a new beginning for our crown jewel of law enforcement," Trump said in a statement announcing Comey's firing.

A senior administration official told NBC News' Mark Halperin that Trump met with McCabe "in the Oval Office this evening for about 30 minutes."

The Daily Beast, citing a federal law enforcement source, reports that rumors "are flying" that McCabe could soon resign or be fired, within the next few weeks.

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