A federal judge on Friday ordered Hillary Clinton to respond in writing to questions about her use of a private email server when she was secretary of state.

US District Court Judge Emmet Sullivan granted conservative legal advocacy group Judicial Watch a partial victory after they sought to question the Democratic nominee in person and under oath as part of a long-running public records lawsuit.

Judicial Watch must submit its questions by October 14, giving Clinton 30 days to respond in a timetable that could push her answers past November's election.

The State Department will also have to release any emails recovered by the FBI's probe into Clinton's server by September 30, according to the court order.

US District Court Judge Emmet Sullivan ordered Clinton to answer questions from Judicial Watch in writing. The conservative legal advocacy filed a public records lawsuit against the State Department

Former Secretary of State Colin Powell (pictured in 2008) said he once sent Clinton a memo touting his use of a personal email account for work-related messages

Judicial Watch pushed for an in-person testimony to better follow up on Clinton's responses, but the presidential nominee argued a deposition would be 'unnecessary', according to Sullivan's memorandum opinion.

She conceded that she could provide information in writing rather than 'repeating her prior statements or stating that she has no knowledge of certain topics.'

Tom Fitton, president of Judicial Watch, said: 'We will move quickly to get these answers. The decision is a reminder that Hillary Clinton is not above the law.'

Judicial Watch has also been granted a sworn deposition from John Bentel, who was formerly in charge of IT security issues at the State Department.

In a 2010 meeting with Bentel, a staff member raised concerns that messages sent or received using the private server could contain documents that needed to be preserved under federal regulations.

Bentel told the staff member that State Department legal staff had 'reviewed and approved' the server— though the inspector general's review found no evidence such a review had ever occurred.

Bentel directed the staff members to 'never to speak of the secretary's personal email system again.'

Clarence Finney, a State Department employee responsible for managing records and FOIA responses, was excused from giving a deposition.

Judicial Watch is among several groups, including The Associated Press, that have sued the State Department over access to government records from Clinton's tenure as the nation's top diplomat between 2009 and 2013.

Republicans are pressing to keep the issue of Clinton's email use alive after the FBI closed its investigation last month without recommending criminal charges.

Powell (left) said he told Clinton his use of personal email 'vastly improved' communications within the department, which at the time did not have an equivalent internal system

In a separate development Friday, former Secretary of State Colin Powell said he once sent Clinton a memo touting his use of a personal email account for work-related messages after she took over at the State Department in 2009.

Powell said he emailed Clinton describing his use of a personal AOL account for unclassified messages while leading the State Department under President George W. Bush.

Powell, a Republican, said he told Clinton his use of personal email 'vastly improved' communications within the department, which at the time did not have an equivalent internal system.

Clinton has used Powell in her public defense of her behavior - which she now says was a 'mistake' - but only as an example of a previous secretary who relied solely on private email to conduct government business.

Powell, a retired Army general and former chairman of the Joint Chiefs of Staff, said he used a secure computer on his desk at the State Department to manage classified information.

Powell relied on a commercially available service to host his personal email account, while Clinton's private server was located in the basement of the New York home she shared with her husband, former President Bill Clinton.