An initial State Department review of former Secretary of State Hillary Clinton's emails concluded that five months' worth of messages were missing from the thousands she turned over to the government last year, though the department now claims it has filled those gaps, reported the Hill.

The admission of gaps was discovered in documents recently obtained by the watchdog group Judicial Watch after a judge ordered the State Department to release them in a Freedom of Information Act lawsuit.

"A five month email gap," said Judicial Watch President Tom Fitton at the group's inaugural Leadership Summit Monday, reported the Daily Caller. "I want an explanation about that."

Aug. 10, Clinton submitted to a federal court a statement signed under penalty of perjury saying she returned all work-related emails that were stored on her private server at her New York home, noted the Washington Times.

"These emails raise questions whether Clinton told the truth last month," said Fitton.

The State Department found there was a "gap" in Clinton's received messages from Jan. 21, 2009, her first day as secretary of state, to March 17, 2009. The department also found a gap in messages sent between Jan. 21, 2009 and April 12, 2009, and again from Dec. 30, 2012, to her last day as secretary on Feb. 1, 2013.

The missing emails are "comparable to the Nixon 18-minute gap" found in the Watergate tapes, said Fitton, adding, "she didn't have the right to determine what's personal and what's work."

In Dec. 2014, Clinton turned over some 30,000 emails that she single-handedly determined were work-related, and then deleted an additional 30,000 that she said were personal in nature, without independent oversight.

"It's malarkey that the emails Clinton withheld were of a personal nature," Fitton told the Summit, according to Newsmax. Her personal emails were "intertwined and indistinguishable" from work-related emails and federal records, he said.

"The Obama administration and Hillary Clinton have taken their cover-up of the email scandal too far," said Fitton. "I suspect that federal courts will want more information, under oath, about the issues raised in these incredible documents."

The documents also show that another one of Clinton's top aides, Cheryl Mills, used a personal email account: cherylmills@gmail.com.

State Department spokesman Alex Gerlach told the Daily Caller that the department is not aware of any gaps in Clinton's emails "with the exception of the first few months of her tenure when Secretary Clinton used a different email account that she advised she no longer has access to."

"There is no 'gap' in Secretary Clinton's sent messages from the December 2012 through the end of January 2013. Upon review, the department has many messages sent by Secretary Clinton during that period, including messages that appear to have been produced directly from her 'sent' mailbox. Future document releases will include emails from this time period. Also, that she didn't use this email in early 2009 has been previously acknowledged/confirmed."