"Secretary Clinton gave a voluntary interview this morning about her email arrangements while she was Secretary," spokesman Nick Merrill said. "She is pleased to have had the opportunity to assist the Department of Justice in bringing this review to a conclusion. Out of respect for the investigative process, she will not comment further on her interview."
The interview occurred at FBI headquarters in Washington, D.C., and lasted approximately three and a half hours, according to a Clinton aide.
"I was happy I got the opportunity to assist the department and bring this to a conclusion," Clinton said in an interview scheduled to air Sunday on NBC's "Meet the Press."
The presumptive Democratic presidential nominee said she still stands by "my answers that I first gave more than a year ago."
The Justice Department declined to comment, and the FBI did not immediately respond to a request for comment.
The FBI is in the final stages of its email-related investigation, looking at how Clinton and her aides handled classified information when she was secretary of state.
The Justice Department's goal is to complete the investigation and make recommendations on whether charges should be filed before the two major party conventions take place toward the latter half of July, according to a source familiar with the investigation.
Officials want ample time to review Clinton's interview and compare it to everything they have discovered in the months-long investigations, according to the source.
Attorney General Loretta Lynch has said she will accept the recommendations of the career prosecutors and investigators regarding the case.
Questions were raised about whether Lynch would be impartial after it was revealed that she and former President Bill Clinton met privately during a chance encounter on the tarmac at Sky Harbor International Airport in Phoenix earlier this week.
"Certainly, my meeting with him raises questions and concerns," Lynch acknowledged on Friday. "It has now cast a shadow over how this case may be perceived, no matter how it's resolved. ... [But] it's important to make it clear that that meeting with President Clinton does not have a bearing on how this matter is going to be reviewed, resolved and accepted by me."
She added, however: "I certainly wouldn't do it again."
Both Lynch and Bill Clinton have insisted the meeting was completely "social," focusing on grandchildren, golf, travel, the Brexit vote, “and things like that," as Lynch put it.
Last year, it was revealed that Clinton had exclusively used her family's private email server for official communications during her tenure as secretary of state. The official communications included thousands of emails that were later marked classified by the U.S. State Department.
Donald Trump kept up his attack on Clinton for her email use, tweeting today that "It is impossible for the FBI not to recommend criminal charges against Hillary Clinton. What she did was wrong!"
It is impossible for the FBI not to recommend criminal charges against Hillary Clinton. What she did was wrong! What Bill did was stupid!— Donald J. Trump (@realDonaldTrump) July 2, 2016
ABC News' Mike Levine, Julia Jacobo and Pierre Thomas contributed to this report.