The U.S. State Department said Friday it has censored 22 emails sent from the home server of former Secretary of State and Democratic presidential front-runner Hillary Clinton. Those emails were deemed highly classified by the State Department.

The information, which was confirmed for the first time Friday by the State Department, came out ahead of the Iowa caucuses, where the former Secretary of State is locked in a tight race with Bernie Sanders for the Democratic presidential nomination. It also surfaced just over a week since it was revealed that Clinton's server contained "special access programme'' or SAP.

"The documents are being upgraded at the request of the intelligence community because they contain a category of top secret information," State Department spokesman John Kirby told the Associated Press on Friday.

He said there were seven email chains being withheld from the public due to the sensitive information they contain, which includes SAP.

Officials of the State Department would not say if Clinton was the one who sent the emails, AP said.

According to reports, the Diplomatic Security and Intelligence and Research bureaus will now try to determine if any of the emails were marked classified at the time of transmission. FBI special agents, around 100 of them, will also investigate and find out whether Clinton violated a subsection of the Espionage Act related to "gross negligence" in handling government documents.

Agents are also trying to discern whether co-mingling of the Clinton Foundation and State Department business violated public corruption laws, WND reported.

Meanwhile, sources told the Daily Mail that the emails were "too damaging" to be released under any circumstances.

"The documents alone in and of themselves set forth a set of compelling, articulable facts that statutes relating to espionage have been violated," said a former senior federal law enforcement officer.

Meanwhile, Clinton campaign spokesman Brain Fallon called the decision to censor Clinton's emails "overclassification run amok."

"We firmly oppose the complete blocking of the release of these emails," Fallon stated. "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."