I am sorry: Hillary Clinton on use of private email

Apologising for using private email server during her term as secretary of state, Democratic presidential frontrunner Hillary Clinton has said "I am sorry" and termed her decision a "mistake."

"I do think I could have and should have done a better job answering questions earlier. I really did not perhaps appreciate the need to do that," Clinton told the ABC news in an interview yesterday.

"What I had done was allowed, it was above board. But in retrospect, as I look back at it now, even though it was allowed, I should have used two accounts. One for personal, one for work-related emails. That was a mistake. I am sorry about that. I take responsibility," she said.

Clinton's acknowledgement of the "mistake" came as the email controversy threatens to derail her presidential campaign. Latest polls indicates she is slipping behind her nearest Democratic rivals in some of the key States and her popularity rating is coming down.

In her interview, Clinton said she did not violate the law as this was allowed at that time.

"As I said, it was allowed and there was no hiding it. It was totally above board. Everybody in the government I communicated and that was a lot of people, knew I was using a personal email.

"But I am sorry that it has, you know, raised all of these questions. I do take responsibility for having made what is clearly not the best decision," she said.

During the interview, Clinton exuded confidence that she would survive the controversy.

"I can survive it. Of course I can. I, as you might guess, have been around a while and there have been lots of, you know, attacks and counter-attacks and questions raised. And I can survive it because I think I am running to be President to do what the country needs done. And I believe the American people will respond to that," Clinton said.

Acknowledging that these are challenging time for her, she said that she is still having a good time. "It's hard, but it's fun. Most of the things that are hard in life are fun," she added.

Clinton is battling declining popularity ratings after it became known that she had used a private email server during her term as the top US diplomat in the first term of US President Barack Obama from 2009-12.