Twenty-two emails from Hillary Clinton's private email server have been marked "top secret" and won't be released, the State Department said Friday.
The emails were not marked as classified at the time they were sent.
"We can confirm that later today, as part of our monthly FOIA productions of former Secretary Clinton's emails, the State Department will be denying in full seven email chains, found in 22 documents representing 37 pages," State Department spokesman John Kirby told reporters.
"The documents are being upgraded at the request of the intelligence community because they contain a category of top secret information," Kirby said.
Clinton campaign spokesman Brian Fallon said that Clinton said the emails should be released and called at least one case, "over-classification run amok."
"We firmly oppose the complete blocking of the release of these emails," Fallon said in a statement. "Since first providing her emails to the State Department more than one year ago, Hillary Clinton has urged that they be made available to the public. We feel no differently today."
The revelations come just three days before the Iowa caucuses, where Clinton and chief Democratic rival Bernie Sanders are running neck-and-neck. Clinton's campaign has been dogged by her use of a private email server, and she has been hammered by her GOP opponents who have accused her of jeopardizing national security.
Sanders was notably dismissive of the email issue during a Democratic debate last year, contending that Americans are sick of hearing about her "damn emails." In a statement Friday afternoon, Sanders largely reiterated that sentiment, saying, "As I said at the first Democratic debate, there is a legal process in place which should proceed and not be politicized. The voters of Iowa and this nation deserve a serious discussion of the issues facing them."
Clinton remained defiant and at times dismissive of the issue for much of 2015. Last September she shifted her tone, apologizing for not using a government issued email address.
Kirby also announced today that 18 emails — from 8 distinct chains — between then Secretary Clinton and President Barack Obama are being withheld from the court -ordered FOIA release, because of the law governing the release of presidential documents. These email exchanges are not classified.
The committee tasked with looking into the security of Clinton's private email servers said the acknowledgement of the top secret documents "underscores the recklessness" of Clinton's use of private email.
"We must assume that every classified piece of information ever stored on her private server is now in the hands of our enemies," Sen. Ron Johnson, R-Wis., chairman of the Senate Homeland Security Committee, said
"We must expedite a thorough and comprehensive investigation of these documents to determine what secrets may have been compromised in order to mitigate the damage."
Meanwhile, the White House put in context a comment at Friday's press briefing by spokesman Josh Earnest regarding the Clinton e-mail issue.
Earnest had been asked if he could with "certainty and confidence" say that Secretary Clinton will not be indicted because of the e-mail scandal.
"That is a decision to be made solely by independent prosecutors. But again, based on what we know from the Department of Justice, it does not seem to be headed in that direction," Earnest said.
Later, asked about the comment, the press office said the Justice Department has not been keeping the White House informed about the investigation. Earnest, the White House explained, was referring to some newspaper accounts and public comments that came out last year.
Officials at the FBI and the Justice Department are nonetheless concerned about the implication of Earnest's statements and have been emphatic that there have been no progress reports on the investigation.