Washington: Democratic 2016 presidential contender Hillary Clinton ran into a new political storm over the use of a private server for sending official emails with reports suggesting that some emailed material contained classified information.
The inspector general for the intelligence community had informed US Congress that some material emailed from the former secretary of state's private server contained classified information, but it was not identified that way, CNN reported.
The IG reviewed a "limited sampling" of her emails and among those 40 reviewed found that "four contained classified (intelligence community) information", IG Charles McCullough was quoted as saying in a letter to Congress.
The four emails in question "were classified when they were sent and are classified now", spokeswoman Andrea Williams told CNN.
McCullough said that State Department Freedom of Information Act officials told the intelligence community IG that "there are potentially hundreds of classified emails within the approximately 30,000 provided by former Secretary Clinton".
Clinton on Friday criticised what she called "a lot of inaccuracies" in reports about the classified emails.
She added that she had released 500 pages of emails and that "I've said repeatedly that I will answer questions" posed by a Congressional panel.
"But I'm also going to stay focused on the issues, particularly the big issues that really matter to American families," she said.
In the past, Clinton has denied sending classified information from her personal sever.
Meanwhile Justice Department issued a statement correcting earlier reports that a probe into emails from Clinton's server during her time as secretary of state was a criminal investigation.
Instead, a Justice Department official said that the agency had "received a referral related to the potential compromise of classified information".
CNN cited sources as confirming both inspectors general have asked the justice department to open an investigation. But there has not yet been a decision on whether to launch a criminal probe.
Following the new report, several Republican leaders renewed their attacks on Clinton with House Speaker John Boehner calling on her to relinquish her server and questioning her judgment.
"If Secretary Clinton truly has nothing to hide, she can prove it by immediately turning over her server to the proper authorities and allowing them to examine the complete record," he said.