Hillary Clinton's top aide, Huma Abedin, and other associates have now been interviewed by the FBI as part of the agency's inquiry into the former secretary of state's use of a private email server, sources told ABC News today.
A source familiar with the probe described the development as a routine part of the review, saying so far no indication of criminal wrongdoing has been found. No date has yet been set for a possible interview of Clinton herself, the source said.
Two weeks ago, FBI Director James Comey said there is no timetable for completing the Clinton-related investigation.
"I get that people care about this investigation, and so we're working very hard to ensure it's done well and promptly," Comey said at an Aspen Security Forum in London.
Amid questions over the security of the server, sources have told ABC News that authorities have found no evidence suggesting the private server was hacked or otherwise breached.
In a statement to ABC News, Brian Fallon, a spokesman for Clinton's presidential campaign said: "From the start, Hillary Clinton has offered to answer any questions that would help the Justice Department complete its review, and we hope and expect that anyone else who is asked would do the same. We are confident the review will conclude that nothing inappropriate took place."
The latest developments were first reported by CNN.
ABC News' Liz Kreutz contributed to this report.
This is a developing story. Please check back for updates.