Washington, May 3 - Several Indian-Americans are among 107 people charged in Medicare fraud schemes involving $450 million in false billings uncovered in an operation across seven cities in the largest US bust in recent history.

Top US law enforcement officials announced the charges were filed in seven metropolitan areas, capping an investigation of several months into efforts to defraud Medicare, Medicaid and other federal health programmes for senior citizens.

At least 91 of the defendants in the case have been taken into custody following an early morning roundup and the execution of 20 search warrants, the officials said.

In Miami, 59 people were charged. Seven defendants were charged in Baton Rouge, Louisiana, nine were charged in Houston, eight were charged in Los Angeles, 22 were charged in Detroit, one was charged in Chicago and one in Tampa.

At least four Indian Americans figured among those charged in Detroit.

While Sachin Sharma, 36, and Dana Sharma, 29, of Michigan and two others were charged for their roles in a $23 million scheme to defraud Medicare, Madhur Thawani, 27, and Ankit Patel, 27, also of Michigan and three others were charged in another $13.8 million scheme to defraud Medicare.

Those arrested include nurses, therapists, social workers and a pharmacist. Charges against ambulance companies for billing to cover unnecessary rides represented a new wrinkle in fraud enforcement, officials said.

FBI Deputy Director Sean Joyce told a press conference here to announce the charges that the FBI is currently investigating more than 2,600 cases of health care fraud.

In 2011, the FBI charged more than 1,600 individuals, and helped secure more than 700 convictions, he said.

(Arun Kumar can be contacted at arun.kumar@ians.in)