During the lawsuit filed against Hillary Clinton by conservative legal watchdog group Judicial Watch, U.S. District Judge Emmet Sullivan ruled on Tuesday that State Department officials and top aides to Clinton should be questioned under oath regarding their use of private email servers throughout her time as secretary of state from 2009 to 2013, the Washington Post reports.

The ruling comes in response to a May 2013 request by Judicial Watch for information regarding Clinton's longtime aide, Huma Abedin. Representatives with the State and Justice departments claim to be aware of the order but made no further comments, while Abedin's attorney has declined to comment at all.

Sullivan set a deadline for April 12, by which the parties must come up with a detailed investigative plan to uncover the nature of the private server that Clinton used. Furthermore, he suggested that in the future he might subpoena Clinton and Abedin to present all emails related to Clinton's private account.

Clinton apologized for the private servers last year and claims that at least some of the inquires into her emails stem from political motivations, according to Reuters.

"This is one of several lawsuits filed by the same right-wing group, which will stop at nothing in pursuing the Clintons, just as they have done since the 1990s," Nick Merrill, a Clinton spokesman, said in an email.

Clinton has already released approximately 50,000 pages of emails to the State Department, which has in turn has released them to the public gradually, according to NPR.

The State Department claims that at least 1,700 of the emails from Clinton's unsecured server contain classified information such as secrets from the country's spy agencies. In addition to Judicial Watch, the Federal Bureau of Investigation (FBI), the State Department's internal watchdog and various Republican-controlled congressional committees are also investigating the arrangement.