Bernard Madoff has left his North Carolina prison's hospital unit and returned to his cell.

The 71-year-old disgraced financier had been transferred to a prison hospital on Dec. 18. Bureau of Prisons spokeswoman Denise Simmons said Wednesday he was transferred back to the medium security section of the complex Monday. She declined to discuss Madoff's health.

Madoff's lawyer has said that Madoff had dizziness and high blood pressure. Prisons officials have said he was not assaulted.

Madoff is serving a 150-year sentence after pleading guilty to fraud and admitting to cheating thousands of investors out of billions of dollars.