Paul Krugman. Reuters/Tim Shaffer Nobel Memorial Prize-winning economist and New York Times op-ed columnist Paul Krugman slammed the FBI's "disgraceful" announcement Friday that it will reopen its investigation into Hillary Clinton's use of a private email server while she was secretary of state.

"It's bad enough having the media do the 'raises questions,' substance-free innuendo thing. Worse when the FBI director does it. Disgraceful," Krugman, a Clinton supporter, wrote on Twitter.

"Comey needs to provide full info immediately. Otherwise he has clearly made a partisan intervention, betraying his office."

James Comey, the FBI director, wrote in a letter to congressional leaders on Friday that investigators had learned of "the existence of emails that appear to be pertinent to the investigation" that compelled agents to continue their probe, which had ended in July with no charges recommended against Clinton.

"The FBI cannot yet assess whether or not this material may be significant," Comey wrote. "And I cannot predict how long it will take us to complete this additional work."

Krugman condemned how Comey handled the entire ordeal, calling his behavior "inexcusable" and "grotesque."

He added that "so far this is a story about Comey and his behavior. We know nothing at all about what if anything this has to do with HRC."

View some of his tweets:

"The announcement has done measurable damage to the Clinton campaign," Krugman continued. "Which was predictable. Comey behavior inexcusable. If Pete Williams is right, this is probably nothing important. Yet here we are, with a potentially huge political impact. The bed has been fouled, and can't be un-fouled."

NBC's Williams had reported earlier that none of the new emails had been found on Clinton's private server.

Krugman was not alone. Many quickly condemned the FBI's handling of the announcement that it would reopen the investigation.

"I have zero faith that anyone will handle this responsibly," former Obama speechwriter Jon Favreau wrote. "It's insane. [Comey] at least owes the country a press briefing — anything more than a vague letter."

"Director Comey should give a more complete explanation. Is this reviewing newly found emails? Is this reopening? Too much at stake," wrote John Weaver, the former campaign strategist for Ohio Gov. John Kasich.

Democratic National Committee Interim Chair Donna Brazile called Comey's letter "irresponsible."

"The FBI has a solemn obligation to remain neutral in political matters – even the faintest appearance of using the agency’s power to influence our election is deeply troubling," she wrote in a statement.

Comey explained why he sent the letter to Congressional leaders in a separate letter to his employees on Friday, acknowleding that "in a brief letter and in the middle of an election season, there is significant risk of being misunderstood."

"We don’t ordinarily tell Congress about ongoing investigations, but here I feel an obligation to do so given that I testified repeatedly in recent months that our investigation was completed," Comey wrote. "I also think it would be misleading to the American people were we not to supplement the record."

Reports emerged later on Friday that the new emails, numbering in the thousands, were uncovered after the FBI seized devices belonging to top Clinton aide Huma Abedin and her estranged husband, Anthony Weiner. Prosecutors issued a subpoena for Weiner's cellphone and other records in late September amid allegations that he had been sexting with a 15-year-old girl.

In a press conference on Friday evening, Clinton implored the FBI to release more information about the newly discovered documents.

“The American people deserve to get the full and complete facts immediately," she said.