FBI Director James Comey testifies before a Senate Judiciary Committee hearing on "Oversight of the Federal Bureau of Investigation" on Capitol Hill in Washington, May 3, 2017. [Photo/Agencies]

WASHINGTON — US President Donald Trump fired James Comey, the director of Federal Bureau of Investigation (FBI), the White House said in a statement Tuesday.

"Today, President Donald J. Trump informed FBI Director James Comey that he has been terminated and removed from office," the statement said.

"President Trump acted based on the clear recommendations of both Deputy Attorney General Rod Rosenstein and Attorney General Jeff Sessions," the statement added.

"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," the statement quoted Trump as saying.

A process to select a new FBI director is underway.

In a letter he sent to Comey earlier Tuesday, Trump said that "While I greatly appreciate you informing me, on three separate occasions, that I am not under investigation, I nevertheless concur with the judgement of the Department of Justice that you are not able to effectively lead the bureau."

"It is essential that we find new leadership for the FBI that restores public trust and confidence in its vital law enforcement mission," Trump said.

Comey was appointed as FBI director in 2013, and has been embroiled in controversy during the presidential election in 2016 after announcing an investigation into the emails of Democratic nominee Hillary Clinton days before election day, a move Hillary said was partially the cause of her loss.

The firing of Comey came as a shock for even many working inside the FBI, and has prompted an uproar of criticism from Democrats.

"You are making a big mistake," Senate Minority Leader Chuck Schumer said in a statement, suggesting dismissing Comey was part of a bid by the administration to "coverup" any wrongdoing regarding the Russian investigations.

Bob Casey, another Democratic Senator, said Comey's dismissal was "Nixonian", citing an incident in 1973 when former US President Richard Nixon fired special prosecutor Archibald Cox over the Watergate scandal.

Comey was the second FBI director that was fired from office. Former President Bill Clinton fired the then FBI Director William Sessions in 1993.