Hillary Clinton tried to delete tens of thousands of emails from the personal account she used during her time as secretary of state, but now it seems the frontrunner for the Democratic presidential nomination is about to learn that the internet is forever.

Platte River, the Denver-based company that managed Clinton's server, told the _Washington Pos_t on Sunday that it has "no knowledge of the server being wiped," indicating that around 31,000 emails deleted by Clinton could be recovered and eventually made public as part of an ongoing FOIA lawsuit filed by VICE News senior investigative reporter Jason Leopold.

"Platte River has no knowledge of the server being wiped," the Post quoted company spokesman Andy Boian as saying. "All the information we have is that the server wasn't wiped."

The controversy over Clinton's use of an unsecured private server to conduct government business while serving as America's top diplomat has cut into her lead in opinion polls for the Democratic nomination to run in the November 2016 election.

Clinton used personal funds to pay a State Department staffer to maintain the email server. The former first lady maintains she did nothing wrong, though she has said she wished she "made a different choice" when considering whether or not to use the unsecured server.

A representative of the Clinton campaign could not immediately be reached for comment on the report from the Post about the deleted emails.

Republican Senators Charles Grassley and Ron Johnson, chairmen of the Judiciary and Homeland Security committees, respectively, said they would push for the deleted emails to be reviewed if they can be recovered, the Post said.

Under a federal judge's order, 15 percent of the 35,000 emails sent by Clinton on the private server are to be released every month. The process has been delayed by intelligence officials combing the messages for information that could be retroactively upgraded to classified status. About 150 of the 7,000 emails released on August 31 were censored because they contain information that the government says it now considers classified.

The Federal Bureau of Investigation is examining the server to see whether any information, including classified information, was mishandled.

Clinton has said she sent no information via email that was classified at the time, and received no material marked that way.

The emails released so far by the State Department have been heavily redacted, but have nonetheless offered a candid peek inside Clinton's inner world. The disclosures have revealed the State Department's immediate response to the WikiLeaks revelations, the delicate US-Israel relationship in the aftermath of the 2008-2009 Gaza War, and discussions about the prosecution of alleged 9/11 mastermind Khalid Sheikh Mohammed.