Kevin Johnson

USA TODAY

WASHINGTON — The State Department is reviewing nearly 15,000 emails as part of a batch of previously undisclosed communications that emerged in the FBI's yearlong investigation of Democratic presidential nominee Hillary Clinton's use of a private server while secretary of State.

Government lawyers acknowledged the action Monday in federal court where the conservative legal group Judicial Watch is seeking release of the messages as part of a separate public records lawsuit.

State Department officials said Monday the communications, contained in 14,900 documents, represent both personal and work-related materials that must now be vetted by authorities before they can be made public.

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"State has not yet had the opportunity to complete a review of the documents to determine whether they are agency records or if they are duplicative of documents State has already produced through the Freedom of Information Act,'' spokesman Mark Toner said.

U.S. District Judge James Boasberg ordered Monday that the government provide the status of its review by Sept. 23.

The existence of the emails, Judicial Watch officials argued, represents a contradiction of previous assertions by the former secretary of State that all work-related emails had been turned over to State for review.

Judicial Watch's lawsuit has continued to keep the Clinton email controversy alive after an FBI investigation was closed last month with a decision not to bring criminal charges against the Democratic nominee.

Last week, the FBI provided a summary of its findings and its interview with Clinton to Congress after Republican leaders challenged the conclusions of federal investigators.

Republican National Committee Chairman Reince Priebus seized on the email review Monday, saying that Clinton "seems incapable of telling the truth.''

"Clinton’s pattern of serial dishonesty is completely unacceptable for a candidate seeking the nation’s highest office, and her refusal to tell the truth and own up to her poor judgment is a preview of how she would conduct herself if elected president,'' Priebus said.

The Clinton campaign, meanwhile, maintained that the nominee had provided State with all work-related communications in her possession in 2014.

"We are not sure what additional materials the Justice Department may have located, but if the State Department determines any of them to be work-related, then obviously we support those documents being released publicly as well,'' Clinton spokesman Brian Fallon said.

Contributing: Heidi Przybyla