Dozens of newly released Clinton emails now classified

A new tranche of 551 email documents from Hillary Clinton's private server released by the State Department on Saturday includes 84 that have been reclassified as "confidential" or "secret."

The former top diplomat, a top White House candidate in the 2016 race, has been dogged by allegations that her use of a private email server while in office, rather than a secure government system, had put US secrets at risk.

The State Department has so far released nearly 46,000 pages of emails out of a total 55,000 pages, all of which are expected to be published by the end of the month.

Saturday's release totals 1,012 partially redacted pages of documents sent to or from her private server.

The emails include 81 that were reclassified as "confidential," the lowest level of classification. Three were upgraded to "secret," a State Department official said.

"The information we upgraded today was not marked classified at the time the emails were sent."

In January, the State Department said 22 of the documents found on the private server contained material considered "top secret" and would not be released publicly.

The FBI is investigating Clinton's use of a private email server.

Clinton has repeatedly denied doing anything wrong but the issue has been a major source of controversy in her presidential campaign.