Istanbul, Sep 9 () - Hillary Clinton apologized for using a private email server while secretary of state, calling the decision, which has dogged her Democratic presidential bid, a "mistake."

The Democratic frontrunner, who is facing eroding support, has long dismissed the email uproar as a manufactured imbroglio.

The lingering email saga has weighed on Clinton's popularity, with a Gallup poll released Friday showing her favorability rating at 41 percent, compared to 51 percent who view her unfavorably -- the lowest level since 1992.

Clinton sent an e-mail to her supporters, expleaning the details of the "mistake":

"I wanted you to hear this directly from me:

Yes, I should have used two email addresses, one for personal matters and one for my work at the State Department. Not doing so was a mistake. I'm sorry about it, and I take full responsibility.

It's important for you to know a few key facts. My use of a personal email account was aboveboard and allowed under the State Department's rules. Everyone I communicated with in government was aware of it. And nothing I ever sent or received was marked classified at the time.

As this process proceeds, I want to be as transparent as possible. That's why I've provided all of my work emails to the government to be released to the public, and why I'll be testifying in public in front of the Benghazi Committee later next month.

I know this is a complex story. I could have -- and should have -- done a better job answering questions earlier. I'm grateful for your support, and I'm not taking anything for granted."