FBI Director James Comey abruptly announced Sunday that a review of newly discovered emails sent or received by Hillary Clinton has not changed his conclusion that the Democratic candidate should not face criminal charges. His announcement came in a letter to congressional lawmakers two days before election day.

Comey said the FBI has worked "around the clock to process and review a large number of emails" obtained from a device belonging to Anthony Weiner, the disgraced former congressman and estranged husband of top Clinton aide Huma Abedin.

He said the review has not changed the bureau's assessment from earlier this year that Clinton should not be prosecuted for her handling of classified information at the State Department.

"I am very grateful to the professionals at the FBI for doing an extraordinary amount of high-quality work in a short period of time," Comey said.

Clinton's campaign welcomed the FBI announcement.

"We're glad this matter is resolved," Jennifer Palmieri, Clinton's communications director, told reporters travelling with the campaign to Ohio.

Clinton's press secretary, Brian Fallon, responded on Twitter.

"We were always confident nothing would cause the July decision to be revisited. Now Director Comey has confirmed it."

We were always confident nothing would cause the July decision to be revisited. Now Director Comey has confirmed it<a href="https://t.co/BMQQx9eRzw">https://t.co/BMQQx9eRzw</a> —@brianefallon

Clinton was infuriated by Comey's decision to alert Congress late last month that the FBI was reviewing new materials, calling it "unprecedented" and "deeply troubling." The decision shattered what had appeared to be Clinton's solid grip on the race and emboldened Republican Donald Trump.

Trump landed in Minnesota for a rally moments after Comey's announcement Sunday. He made no direct mention of the FBI decision and continued to insist — without evidence — that Clinton would be under investigation during her potential presidency.

"She's protected by a rigged system," he said. "She shouldn't even be allowed to run for president."

Trump's campaign manager Kellyanne Conway said on Twitter the latest FBI conclusion means that Clinton "still was reckless and careless and still lied about classified info."

If FBI conclusions remain unchanged, that means she still was reckless & careless, still lied about classified info, lied re: # of devices —@KellyannePolls

The FBI began investigating the handling of classified material on Clinton's private server in New York shortly after she announced her bid in April 2015. Last July, in an extraordinary public statement on an ongoing case, Comey announced he was not recommending criminal charges against Clinton and called the decision "not even a close call."

But he also delivered blistering criticism of Clinton, calling her and her team "extremely careless" with her handling of national secrets.

The latest emails were found on Weiner's computer. Weiner is under investigation by federal authorities for online communications he had with a 15-year-old girl.

Upon discovering emails thought to be potentially pertinent to the Clinton email investigation, Comey advised Congress that investigators would review the messages to see whether they were classified. The FBI subsequently obtained a warrant to begin the process of going through the emails.

In his letter to Congress on Sunday, Comey said the FBI had reviewed all new emails to and from Clinton and that nothing had changed its July conclusion. But the letter did not address how the messages wound up on Weiner's computer and what, if anything, the announcement means for Abedin.

Abedin's attorney, Karen Dunn, has said Abedin learned from media reports about the possibility that her emails had been found on a laptop belonging to Weiner.

Criticism from both parties

Republicans did not ease up on their criticism of Clinton after Comey's announcement.

"She simply believes she's above the law and always plays by her own rules," House of Representatives Speaker Paul Ryan said in a statement, arguing that Clinton's use of a private email server "compromised our national security."

Republican National Committee Chairman Reince Preibus said that while the probe had not led to criminal charges, it produced evidence that Clinton broke the law and "repeatedly lied to the American people about her reckless conduct."

Meanwhile, Democrats did not let Comey and the FBI off the hook. U.S. Sen. Dianne Feinstein of California said Sunday's announcement made Comey's earlier letter "even more troubling" for creating a false impression about the inquiry.

"I believe the Justice Department needs to take a look at its procedures to prevent similar actions that could influence future elections," she said.

Clinton hasn't addressed the FBI's decision, but Trump spoke about it during an evening stop in Michigan.

He challenged the FBI's ability to review the newly discovered emails so quickly and continued to argue Clinton was being protected by a "rigged system."

"You can't review 650,000 emails in eight days," Trump said. "You can't do it folks. Hillary Clinton is guilty."