(cnn) the state department announced friday that it will not release 22 emails from former secretary of state hillary clinton because they contain "top secret" information, the highest level of government classification.









the decision, coming three days before the iowa caucuses, could provide fodder for clinton's political opponents, especially republicans, who are likely to make note of the emails' "top secret" designation. clinton's email use has haunted her on the campaign trail since it became public early last year that she maintained a private server while leading the state department.









state department spokesman john kirby said the documents, totaling 37 pages, were not marked classified at the time they were sent, but are being upgraded at the request of the intelligence community because they contain sensitive information.









but, kirby said, a separate review by the bureaus of diplomatic security and intelligence and research is being held into whether the information in the emails was classified at the time they were sent and received. he would not say when the review began or how long it would go, and acknowledged it's possible there could be classified emails that weren't marked as such.









"it's certainly possible that for any number of reasons, traffic can be sent that's not marked appropriately for its classification. that is certainly possible," kirby said.









but he added that he wasn't going to make any judgments about this particular case.









"all i can tell you definitively is it wasn't marked classified at the time it was sent," kirby said.









a senior state department official said the review "began very recently" and was initiated by the state department, but the official wouldn't say what prompted it.









a spokesperson for the intelligence community's inspector general declined to comment.









kirby also said 18 emails, comprised of eight email chains between clinton and president barack obama, are being "withheld in full" to "protect the president's ability to receive unvarnished advice and counsel." but, kirby said, they "have not been determined to be classified" and said they will "ultimately be released in accordance with the presidential records act."









"i'd love for people to see what i did and i hope that will happen," she said.









brian fallon, a spokesman for clinton's campaign, said in a statement that friday's announcement was a case of "over-classification run amok" and reiterated clinton's position that the emails be made public.









but later friday, fallon declined to say whether clinton would ask obama to declassify the emails when pressed by cnn's wolf blitzer on "the situation room."









"the president easily could declassify all of these emails if she asked him and if he agreed, right?" blitzer asked.









"i'd really be surprised if this has risen to the president's level," fallon replied. "because, again, this a mundane matter of fulfilling a foia request."









asked friday if he had "certainty and confidence" that clinton will not be indicted over the email controversy, white house press secretary josh earnest said any decision to prosecute clinton would rest with the justice department.









"that is a decision to be made solely by independent prosecutors," earnest said. "but again, based on what we know from the department of justice, it does not seem to be headed in that direction."









the state department released more than 900 of clinton's emails friday -- 242 of which received classification upgrades: 11 to "secret" and 209 more to "confidential," along with the 22 emails containing "top secret" information -- but the release fell well behind the judge-imposed timetable for producing all of her emails.









among the most interesting correspondence:









this month's release was supposed to be the final one and include just over 9,000 pages of documents -- the largest number to date.









that delay was then compounded by a huge snowstorm that shut down the federal government for several days, according to the state department's motion.









several prominent republicans, including presidential hopefuls, quickly condemned clinton, the democratic 2016 front-runner, over friday's developments.









"the new e-mail release is a disaster for hillary clinton. at a minimum, how can someone with such bad (judgment) be our next president?" gop front-runner donald trump tweeted.









florida sen. marco rubio said clinton's email use was a "disqualifier" for the white house.









"hillary clinton put some of the highest, most sensitive intelligence information on her private server because maybe she thinks she's above the law," rubio said at a town hall event in clinton, iowa.









texas sen. ted cruz told conservative radio host hugh hewitt that clinton's email controversy would seriously imperil her presidential aspirations.









"we are talking about serious offenses for which the obama justice department threw the book at general (david) petraeus," cruz said. "and justice needs to be enforced fairly and impartially."









and republican national committee chairman reince priebus tweeted that clinton and the obama administration have "obfuscated and misled at every available opportunity," adding that she has "removed all doubt that she cannot be trusted with the presidency."









but rep. adam schiff, d-california, the ranking democrat on the house intelligence committee, said classification determinations "are often very complex."









"it's important to remember that none of these emails had any classification markings at the time they were sent, and secretary clinton and her staff were responding to world events in real time without the benefit of months of analysis after the fact," schiff said.









meanwhile, clinton's top democratic 2016 rival, vermont sen. bernie sanders, said in a statement that "there is a legal process in place which should proceed and not be politicized."









"the american people are sick and tired of hearing about your damn emails," he said then to applause.
state department will not release 22 'top secret' clinton emails
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