A federal judge on Thursday backed a request by one of Hillary Clinton's top aides from her time at the State Department to prevent video of her testimony in ongoing legal proceedings from being released to the public, CNN reports.

In a filing Wednesday, attorneys for former State Department chief of staff Cheryl Mills asked Judge Emmet Sullivan to bar the conservative watchdog group Judicial Watch from releasing the video, which is part of a Freedom of Information Act (FOIA) lawsuit related to Clinton's use of a private email server as secretary of state.

Mills' lawyers say they asked Judicial Watch directly to withhold the video, but the group refused, according to CNN.

"That refusal raises a serious concern that Judicial Watch plans to use the recording of Ms. Mills' deposition, and exploit her image and words, as part of a partisan attack against Secretary Clinton and her presidential campaign," they wrote. "Judicial Watch's long-standing antagonism to the secretary is a matter of public record."

Judicial Watch countered with their own filing Thursday, arguing there was a public interest in the case.

But while Sullivan said he agreed the public had "a right to know details related to the creation, purpose and use of the clintonemail.com system," he was persuaded by Mills' argument that the public interest could be served by releasing the transcripts without accompanying video recordings.

Clinton's use of a private server in her New York home for her government work is being investigated by the Federal Bureau of Investigation, the State Department's internal watchdog and several Republican-controlled congressional committees.

Clinton has said she used private emails out of "convenience", though she has also admitted it "would have been better" to have two accounts to separate work and personal emails.

Earlier this month, reported CNN, Sullivan approved Judicial Watch's request to interview current and former State Department aides in an effort to explain the circumstances under which Clinton was able to establish a private email server as secretary.

The group, which has filed more than a dozen FOIA lawsuits against the State Department in the past year, many of which have shed light on Clinton's email practices, will interview Mills on Friday, the news network said.

Regardless of how Sullivan rules with respect to Mills' request, Judicial Watch will be able to release a written transcript of their deposition interview.

In February, Sullivan ruled that State Department officials and aides to Clinton should be questioned under oath about whether her private email system was an effort to skirt open records laws.

Judicial Watch is seeking to interview Clinton as part of a separate lawsuit.

Mills’ request came the same day a State Department Inspector General's report criticized both Clinton and the State Department for failure to properly archive communications.

Clinton was unfazed by the report and said on Thursday it would not affect her presidential campaign.