Personal and work-related emails that Hillary Clinton said had been deleted from her email server have been recovered by the FBI, US media reported.

Clinton, the frontrunner for the 2016 Democratic Party presidential nomination, has been dogged for months by revelations that she used a private email account and home server in lieu of the official government email system while she was secretary of state from 2009 to 2013.

Clinton said the server was wiped clean after aides determined which messages were personal and which were work-related and should be turned over to the State Department.

The New York Times, however, said Tuesday that the FBI had found the emails, citing two government officials, one of whom said the process of recovery had not been too difficult.

The Times added that it was unknown whether the FBI had found all 60,000 of Clinton's emails.

In a recent court filing, the US Department of Justice said that Clinton had the right to delete messages from her personal e-mail account that she deemed non-work related while she was secretary of state.

"There is no question that former Secretary Clinton had authority to delete personal emails without agency supervision -- she appropriately could have done so even if she were working on a government server," the Justice Department wrote in a document filed in US District Court in Washington.

The Washington Post had previously reported that the company that managed Clinton's private e-mail server said it had "no knowledge of the server being wiped," suggesting that deleted emails could be recovered.