PwC Denies Romney's Tax Returns Were Stolen From Its Offices

Mitt Romney
Mitt Romney

The giant accounting firm PricewaterhouseCoopers says a claim by a hacker group that it stole Republican Presidential candidate Mitt Romney’s tax returns from an office in Tennessee does not appear to be true.

"We are aware of the allegations that have been made regarding improper access to our systems,” said Chris Atkins, the managing director of US public relations for the firm. “ We are working closely with the United States Secret Service, and at this time there is no evidence that our systems have been compromised or that there was any unauthorized access to the data in question."

The Romney campaign similarly told CNBC that it was aware of the claim. A Romney spokesman said “proper authorities” are investigating the allegation.

The claim appeared Wednesday on the website Pastebin.com, the same venue that had been used by Anonymous affiliated hackers to release what they said were one million unique identifying numbers of Apple computer products. (Read More: FBI Denies Hackers' Claim Of Apple ID Theft)

In the statement posted on the website, the alleged hackers wrote, “we were able to gain access to your network file servers and copy over the tax documents for one Willard M Romney and Ann D Romney. We are sure that once you figure out where the security breach was, some people will probably get fired but that is not our concern.”

The person also demanded that $1 million worth of the online currency Bitcoins be transferred to an account by September 28 or the hackers would post the full tax returns on the Internet. The claim said the information had been obtained from an accounting office at 830 Crescent Centre Drive in Franklin, TN.

—By CNBC's Eamon Javers