The U.S. State Department, for the first time, is saying that former secretary of State Hillary Clinton's unsecured home computer server contained 22 emails with top secret information and said those emails would not be released to the public.
Spokesman John Kirby said Friday the material includes seven email chains covering 37 pages of messages. He said the emails would not be disclosed, even with blacked-out boxes, as the agency released more of the emails from Clinton's tenure as the country's top diplomat.
Kirby said the documents were not marked classified at the time they were sent, but are being upgraded now at the request of U.S. intelligence officials. State Department officials are checking whether any of the material was actually classified at the time it passed through her server, but Clinton has repeatedly said she did not send or receive any such classified material.
The development came three days before Clinton, the leading contender for the 2016 Democratic presidential nomination, competes in the Iowa caucus. It is the first voting in the state-by-state nominating contests to pick Democratic and Republican candidates to square off in next November's national election to replace President Barack Obama when he leaves office in a year.
Clinton has been the national front-runner for the Democratic nomination, but is locked in a tight contest in the rural state of Iowa against Vermont Senator Bernie Sanders, who calls himself an independent Democratic socialist.
Sanders has dismissed the controversy over Clinton's emails, but Republican presidential candidates have regularly attacked Clinton's use of the unsecured email link for official business, with some contending she should be criminally charged for the possible security lapse.
Other candidates' reactions
One Republican presidential candidate, Florida Senator Marco Rubio, said at a debate Thursday that "her first acts as president may very well be to pardon herself."
The leading Republican contender, billionaire real estate tycoon Donald Trump, tweeted, "How can anyone with such bad judgment be our next president?"
The Clinton campaign demanded Friday that the emails be released in full. A campaign statement said the development is an example of "bureaucratic infighting" over the degree of classification that should be placed on the emails and "over-classification run amok."
Private email account
Clinton has been at the center of a controversy since it was discovered that she used her private email account for official business while serving as secretary of state from 2009 to 2013, during Obama's first White House term.
Clinton has asked the State Department to release her emails in order to defuse the controversy, but it is taking officials months to sort through all the material to determine whether there is classified information in them.
State Department officials have said that using a private email account was not prohibited and that Clinton never shared classified information over the account. But critics say it may have been a way for her to hide her communications and that use of the unsecured server at her home outside New York City left it vulnerable to overseas hackers.
Clinton initially said the private server was a matter of convenience, but later conceded it was a mistake.