The number of Hillary Clinton emails flagged for potentially classified content has grown to more than 300, Fox News has learned -- with the potential to grow even more as officials scramble to screen the documents.

The State Department revealed the updated count in a federal court filing, which pertained to Clinton emails sent to other agencies for review. An official familiar with the investigation confirmed to Fox News that, as referenced in that filing, the department has recommended 305 of Clinton's emails be sent to various agencies for review to see whether they contain classified information.

The number could continue to rise as officials comb through more documents; the past three State Department releases have contained a total of 63 classified emails to date.

Clinton's presidential campaign has insisted she never exchanged emails marked classified at the time while secretary of state. "She viewed classified materials in hard copy in her office or via other secure means while traveling, not on email," campaign Communications Director Jennifer Palmieri said in an email to supporters last week.

But the steady trickle of information about sensitive details crossing her server, which she only recently gave to the FBI, has complicated her presidential bid.

On the trail, she recently tried to downplay the controversy with a joke. "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.

Asked about the quip in an interview with Fox News on Monday, New Jersey Gov. Chris Christie said, "Her arrogance is breathtaking."

"I worked for the federal government for seven years as a U.S. attorney. It was made clear to all of us when we walked in the door, official business is done on your official email account," said the GOP presidential candidate.

The State Department came up short in the last email release, unable to meet the court-ordered mark of releasing 15 percent of the emails by July 31.

But The Washington Times reported Monday that officials say they are getting back on track. As part of that process, the Times first reported, the department told the U.S. District Court for the District of Columbia on Monday that out of a sample of 20 percent of Clinton's 30,000 emails, reviewers recommended 305 (about 5 percent) be sent "for referral to their agencies for consultation."

Asked for comment on the filing, a State Department official said intelligence community reviewers "are conducting a relatively simple screening process to determine whether there are IC equities in the emails." The emails are sent for "consultation" when a reviewer identifies such an "agency equity" in an email.

The official said these referrals are a normal part of the process and do not mean the consulted agency will propose a particular outcome. Rather, the official said, the agencies are just being asked to review them.

A court has set up a schedule for the next several months for Clinton emails to be released by the State Department.

Fox News' Ed Henry, Jake Gibson and Lucas Tomlinson contributed to this report.