A White House official who now chairs Hillary Clinton's campaign once asked Clinton's chief of staff, Cheryl Mills, if she had a "personal email" where he could send her some materials outside the State Department's official channels.

John Podesta, then President Obama's counselor, emailed Mills' government account in Sept. 2009 to ask if she had a personal address and informed her that he was planning to meet with "Rahm," likely Obama's then chief of staff Rahm Emanuel.

Mills forwarded the message, which was made public in a small batch of records released by the State Department on Friday, to Clinton.

The email underscores concerns that Clinton and her staff used personal email addresses to keep conversations out of the public's purview.

Mills was among three top aides to Clinton who were forced by a Freedom of Information Act lawsuit to hand over official emails from their personal accounts after it was discovered that they used non-"state.gov" email to communicate for government business.

Clinton has claimed she used a personal email exclusively for convenience.

However, that defense has been called into question following the discovery of more than 1,300 classified emails, including 22 emails that were upgraded to "top secret" Friday.