Hours before FBI Director James Comey was fired Tuesday, the bureau said he misspoke last week when he told lawmakers that Hillary Clinton's top aide, Huma Abedin, had forwarded "hundreds and thousands" of emails to the laptop of her husband, former Rep. Anthony Weiner.

In a letter sent Tuesday to Senate Judiciary Committee Chairman Chuck Grassley, R-Iowa, the FBI said investigators had identified 49,000 emails that were "potentially relevant" to the investigation of Clinton's private email server. Of those, the letter said, investigators determined that "two e-mail[sic] chains containing classified information were manually forwarded to Mr. Weiner's account."

Another ten chains were found on Weiner's computer "as a result of backup activity," the FBI letter continued.

Comey had told the Senate Judiciary Committee that it appeared Abedin made a “regular practice of forwarding emails to [Weiner]" so he could print them out and deliver them to Clinton.

"My understanding is that his role would be to print them out as a matter of convenience," Comey said.

During his testmony last Wednesday, the FBI director was challenged on statements made to Congress Oct. 28, when he alerted lawmakers to the discovery of new emails that he said were potentially connected to the Clinton email case and would need to be reviewed.

The FBI said it discovered thousands of emails on a laptop belonging to Weiner, leading federal authorities to revisit the Clinton email investigation.

“It makes me mildly nauseous to think that we might have had some impact” on the election, Comey said.

The FBI contacted Congress on Nov. 6, the Sunday before Election Day and said its email review had turned up nothing to change its original recommendation against prosecution.

In explaining those decisions, Comey told Congress that the FBI was interested in Weiner's laptop because agents could see that there thousands of emails on the device, including what they thought might be "the missing e-mails from her first three months of Secretary of State."

Comey said the FBI had concluded that neither Weiner nor Abedin had committed a crime in their handling of email.

With respect to Abedin, he said, "we didn't have any indication that she had a sense that what she was doing was in violation of the law. Couldn't prove any sort of criminal intent."

Clinton said last week she was confident she was on track to winning the 2016 presidential race but that two things derailed her: Comey’s initial letter notifying Congress he had reopened the private server investigation, as well as the release of campaign chairman John Podesta’s emails that were allegedly stolen by Russian hackers and released online.

Fox News' Jake Gibson and Mike Emanuel contributed to this report. The Associated Press also contributed to this report