Ninety-one people including doctors, nurses and other medical professionals have been charged with committing $430 million in Medicare fraud in seven U.S. cities, authorities said on Thursday.

An investigation coordinated by the U.S. Justice Department and the Department of Health and Human Services uprooted alleged false billing schemes involving $230 million in home health services, over $100 million in mental health services and $49 million from ambulance transportation.

Charges range from healthcare fraud and conspiracy to wire fraud, kickback violations, identity theft and money laundering. The announcement marks the latest case in a concerted crackdown against Medicare fraud by an interagency Medicare fraud strike force.

The strike force was created under the healthcare reform law as a means of curbing waste, fraud and abuse within the $590 billion Medicare program that provides healthcare benefits to nearly 50 million elderly and disabled beneficiaries.