Sept 7 (Reuters) - U.S. authorities are probing claims of fraud that Cameron Winklevoss, the co-founder of crypto firm Gemini Trust Co, has made against the Digital Currency Group (DCG) and its founder Barry Silbert, according to a source familiar with the inquiry.

Winklevoss has said that DCG and Silbert misrepresented the financial health of DCG's lending arm Genesis, which filed for bankruptcy in January. Gemini was the largest creditor of the bankrupt firm and is suing DCG and Silbert.

DCG has denied any wrongdoing. A spokesperson for DCG declined to comment on the inquiry but said that the firm "always conducted its business lawfully and with the highest ethical standards" and that it assists regulators when asked.

Federal prosecutors in New York and investigators from the FBI and the Securities and Exchange Commission asked Winklevoss about his claims during an interview in recent months, the source said.

Bloomberg was first to report the authorities' interest in the matter and previously said that federal prosecutors and the SEC were investigating DCG's financial dealings.

A spokesperson for the federal prosecutors declined to comment.

The SEC, FBI and Gemini did not respond immediately to requests for comment. Authorities have not accused DCG or Silbert of any misconduct and investigations do not always lead to charges. (Reporting by Chris Prentice in New York and Jaiveer Singh Shekhawat in Bengaluru; Editing by Devika Syamnath and Cynthia Osterman)