Rep. Michael Grimm (R-N.Y.) was indicted on fraud charges in connection with a Manhattan health-food restaurant he partly owned. He faces up to 20 years in prison if convicted. (Jonathan Ernst/Reuters)

Rep. Michael G. Grimm, the lone Republican member of New York City's congressional delegation, said federal charges filed against him last month were politically motivated.

"There's no question anymore that it was a witch hunt from Day One," Grimm said Tuesday during an interview on Geraldo Rivera's morning talk radio show. "It's very simple — it was always politically motivated. This was about silencing the one voice in opposition."

The remarks, first reported by the New York Observer, came as Grimm continues to maintain his innocence despite being indicted on 20 counts, including tax fraud and hiring illegal immigrants when he ran a health-food restaurant before his election to Congress.

Grimm, 44, was elected in 2010 to represent Staten Island and parts of Brooklyn. Before his election, he ran a restaurant called "Healthalicious" — and during that time, prosecutors allege, Grimm routinely hired workers who did not have legal papers to work in the United States and then paid them off the books, in cash, to avoid paying the full amount he owed the state and federal government in payroll taxes.

The congressman has insisted that he will not resign and that he will seek reelection this year.

"I'm going to fight these charges all the way, and I'm going to win reelection," he said.

The full audio of the interview has been posted by the Observer.