WASHINGTON –US Democratic presidential front-runner Hillary Clinton on Tuesday got unexpected backing from her main rival in the primary election as controversy around her private email setup continues to dog her campaign.

In a rare move to show party unity, Senator Bernie Sanders, the runner-up in polls in the Democratic presidential field, came to Clinton's aid for her exclusive use of a private email account and server as the top U.S. diplomat in the first primary debate of the Democratic Party in Las Vegas.

"Let me say something that may not be great politics. But I think the secretary is right, and that is that the American people are sick and tired of hearing about your damn emails," Sanders said. "Enough of the emails. Let's talk about the real issues facing America."

Sanders' remarks came only seconds after Clinton scrambled to divert discussions away from the email scandal while echoing her previous remarks that she had made "a mistake" of setting up her private email system while serving as the secretary of state.

"Tonight, I want to talk not about my emails, but what the American people want from the next president of the United States," Clinton said.

At a press conference in March, Clinton said she had exchanged about 60,000 emails from her private email account during her stint in the Obama administration, among which about half were personal and thus deleted. The Clinton camp turned over the other half, 30,000 emails in total, to the State Department last year.

Clinton's Republican rivals have long claimed that Clinton had deleted certain work-related emails, mainly on the 2012 Benghazi attacks that claimed four American lives, including the U.S. ambassador to Libya, to protect herself.  (Xinhua)