President Donald Trump alleges that former FBI Director James Comey "fixed" last year's investigation into White House rival Hillary Clinton's use of a private computer server for classified emails.

President Donald Trump accused James Comey Wednesday of fixing a probe into Hillary Clinton's email last year, pointing to a heavily censored email released by the FBI as evidence.

The email, released Monday, was described by the FBI as "drafts" of Comey's July 5, 2016 statement in which he announced that the investigation into Clinton's use of a private email server as secretary of state had concluded and no charges would be brought.

The documents were censored in their entirety except for the headers in an email Comey sent to top aides May 16, and a follow-up email sent by one of his aides to other FBI officials requesting comments "on this statement so we can roll it into a master doc for discussion with the Director at a future date."

"Wow, FBI confirms report that James Comey drafted letter exonerating Crooked Hillary Clinton long before investigation was complete," Trump said via Twitter.

"Comey stated under oath that he didn't do this -- obviously a fix? Where is Justice Dept?" he said.

"As it has turned out, James Comey lied and leaked and totally protected Hillary Clinton. He was the best thing that ever happened to her!"

Comey has denied manipulating the results of the Clinton investigation, which figured large in the heated presidential election campaign.

Trump fired Comey on May 9, 2017 citing Comey's investigation into alleged links between the Trump presidential campaign and Russian interference in the election, as well as Comey's alleged protection of Clinton.

In September, amid the first reports of Comey's draft clearance letter on Clinton, legal specialist and Comey friend Benjamin Wittes argued there was nothing wrong with preparing a statement well ahead of time when an investigation's result is apparent.

"There is nothing surprising about this news that Comey began drafting what became the declination statement early," he said via Twitter.

"By May, after 9 months of investigation, unless HRC (Clinton) lied to the FBI or it found something new, this was headed for a declination."