The State Department told a federal court Monday that more than 300 of former secretary of state Hillary Clinton's emails have now been flagged for containing potentially classified content.

An official familiar with the matter told The Washington Times that after screening about 20 percent of the 30,000 emails Clinton turned into the State Department, 305 emails, or 5.1 percent, will have to be sent to various intelligence agencies to be screened to see whether they contain classified information. The Times notes that if investigators continue to find potentially classified information at the current rate, more than 1,500 messages will have to be further evaluated.

Clinton, currently the Democratic front-runner in the 2016 presidential race, has repeatedly insisted she never sent or received classified emails during her tenure as secretary of state.

"I never sent classified material on my e-mail, and I never received any that was marked classified," she said Saturday, reported the New York Post. "The State Department has confirmed that I did not send nor receive material marked classified or send material marked classified."

However, the Times reported Sunday that the State Department has identified at least 60 emails from her unsecured private server that definitely contain classified information. One of the emails contains classified information of an intermediate level, while the rest had information classified at the lowest level.

That's in addition to two emails discovered last week by the intelligence community's inspector general Charles McCullough III which allegedly contain information about the U.S. drone program that is classified as Top Secret/Sensitive Compartmented Information, reports Business Insider.

Clinton recently turned over her server to the FBI, which is conducting a criminal probe into her use of the private server to see how much classified information passed through the system.

In an effort to downplay the probe at a campaign stop in Iowa on Friday, Clinton joked that her new Snapchat account automatically deletes emails. "By the way, you may have seen that I recently launched a Snapchat account. I love it, I love it. Those messages disappear all by themselves," she said, reported Fox News.

Nearly two years after leaving the State Department, Clinton turned over 30,000 emails for record-keeping purposes that she determined were work-related but only after unilaterally deleting an additional 30,000 that she decided were personal in nature. She then reportedly wiped the server clean. The IT firm hired by Clinton to oversee her private server after she left the State Department told ABC on Sunday that it is "highly likely" a backup copy of the server was made, meaning those deleted emails could still be recovered by investigators.

Last week, Clinton submitted to a federal judge a statement signed under penalty of perjury declaring that she turned over all emails related to her work at the State Department.

But the chairman of the House Benghazi Committee, Rep. Trey Gowdy, R-S.C., told ABC on Sunday that Clinton's signed statement is false because his committee already has 15 work emails that she did not turn over.

"I read that statement and if you read that statement, you'll know why people hate lawyers as much as they do. I don't read the statement that way, and I can't read the statement that way, because I know that to be false," Gowdy said, reported Breitbart. "Remember those 15 emails that Sidney Blumenthal gave our committee that she did not turn over to the State Department? All 15 of those related to her public records. So, we know for a fact, that she did not turn all over all records and all documents to the State Department. So, how she can represent that to a federal judge under oath, is something I suspect at some point that judge will ask her."

When Gowdy was asked whether he thinks Clinton is lying, he replied: "I don't use the word lie, I'd just tell you it's false. Whether or not she knew it was false at the time she said it, you're going to have to ask her. I can just tell you that we found 15 documents that should have been produced to the State Department, that she did not produce to the State Department. But that's one of the five explanations she's given with respect to her email arrangement that has also proven to be false. So, whether she's just terribly mistaken a lot, or whether there's an intent to deceive, I'm not smart enough to be able to answer that question. I can just tell you this, she's wrong."