Story highlights Citizens United is asking for emails between four Clinton aides

The emails were supposed to have been shared by July 21

Washington (CNN) Justice Department lawyers are asking for a two-year extension to process emails from Hillary Clinton's aides in order to produce correspondence requested by a conservative advocacy organization.

Lawyers this week said they were unable to satisfy a Freedom of Information Act request -- the deadline for which is later this month -- as quickly as once anticipated and now need until October 2018 to produce the records for Citizens United.

Citizens United is asking for emails between four Clinton aides -- Michael Fuchs, Melanne Verveer, Cheryl Mills and Huma Abedin -- to or from people associated with two Clinton-associated groups: the Clinton Foundation and Teneo Holdings. Teneo is a consulting firm that employed Abedin at the same time she worked for Clinton at the State Department.

"As it began processing these documents, however, (the State Department) determined that the volume of responsive materials was much greater than initially estimated because its initial search had inadvertently excluded potentially responsive materials," the lawyers write in the filing on Wednesday, estimating that there are still 13,679 pages of records to review.

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