US President Donald Trump has fired the director of the FBI over his handling of the inquiry into Hillary Clinton's emails, the administration says.
The White House shocked Washington by announcing that James Comey "has been terminated and removed from office".
But Democrats said he was fired because the FBI was investigating alleged links between the Trump campaign and Russia.
The move came as it emerged Mr Comey gave inaccurate information about Mrs Clinton's emails to Congress last week.
Mr Comey was addressing FBI agents in Los Angeles when, according to Politico and the New York Times, he learned he had just been fired when he saw the news on television.
The 56-year-old - who was three and a half years into his 10-year term as FBI director - reportedly laughed, thinking it was a prank.
The White House said the search for a successor would begin immediately. It is only the second time for the head of the FBI to be fired.
Why does the administration say Comey was fired?
President Trump wrote in a letter to Mr Comey that he agreed with US Attorney General Jeff Sessions' recommendation that "you are not able to effectively lead the Bureau".
Mr Sessions said the Department of Justice was "committed to a high level of discipline, integrity, and the rule of law", and "a fresh start is needed".
Many have expressed surprise that Mr Comey should be fired for his handling of the investigation into Mrs Clinton's use of a private email server for sensitive government business, given that Mr Trump once praised the FBI director's conduct in the matter.
In the final days of the presidential campaign, Mr Trump told a rally it "took guts" for Mr Comey to reopen the inquiry. "What he did brought back his reputation," Mr Trump said.
But on Tuesday, Deputy Attorney General Rod Rosenstein said he "cannot defend the director's handling of the conclusion of the investigation of Secretary Clinton's emails, and I do not understand his refusal to accept the nearly universal judgement that he was mistaken".
"Almost everyone agrees the director made serious mistakes; it is one of the few issues that unites people of diverse perspectives."