The new submission comes after the State Department had previously said it turned over all records the House Select Committee on Benghazi had requested and as the agency reviews Clinton’s e-mails for public release.

The official said the new documents were found as the agency undertook a new review of Clinton’s correspondence in advance of Clinton’s much-anticipated Oct. 22 appearance before the committee. The official, speaking on behalf of the agency, requested anonymity due to the sensitivity of ongoing reviews.

The discovery of additional e-mails, first reported Friday by the Daily Beast, underscored the growing tension between the GOP-led House committee and officials at the State Department as controversy has swirled about Clinton’s e-mail practices while she was secretary.

The State Department had previously submitted 296 e-mails related to Benghazi to the committee. In June, agency spokesman John Kirby told reporters that the committee had expanded its request for documents related not just to Benghazi but to Libya more generally.

But a spokesman for committee Chairman Rep. Trey Gowdy (R-S.C.) denied that the panel had changed the scope of its inquiry. The spokesman, Jamal Ware, said the planned submission confirmed that the department had “failed to previously disclose all Libya and Benghazi-related messages from the former secretary.”

In December 2014, Clinton gave the State Department copies of more than 30,000 e-mails she sent and received using a private account during her four years as secretary.

Also Friday, the State Department confirmed that the Defense Department has given the agency a 2009 e-mail chain between Clinton and David Petraeus, who was then commander of the U.S. Central Command. The e-mail chain had not been provided to the department by Clinton.

The discovery, first reported by the Associated Press, was significant because the chain was not included in the package of work-related e-mails Clinton had submitted to the State Department. Clinton has said she deleted 31,000 personal e-mails, but Republicans have questioned whether she withheld any e-mails that dealt with public business.

Clinton’s campaign has said she did not turn over e-mails from before March 2009 because she initially used a different account.

Kirby said the e-mails in question date from January and February 2009 and their omission from State’s records would be examined by the department’s inspector general.

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