WASHINGTON (AP) — The government says 300 people have been charged this year in health care fraud sweeps across the country. That includes physicians, clinic owners and other health care professionals accused of bilking Medicare.

In all, the fraudulent billings allegedly totaled $900 million, the Justice Department said. Authorities called it the largest-ever national Medicare fraud dragnet.

The Justice Department says the defendants billed for care that was not necessary or services that were not rendered. The sweep spread from southern California to southern Florida and Houston to Brooklyn, New York.

While the individual cases may be unrelated, law enforcement agencies often coordinate the announcement of health fraud charges and arrests to send a message to fraudsters and the general public alike. Health care fraud costs tens of billions of dollars annually.