SAN JUAN, Puerto Rico (AP) — Members of a group accused of generating $650 million in revenue by selling prescription drugs not approved by the FDA to pharmacies in the U.S. have been arrested in one of the largest cases of its kind, federal officials said Thursday.

The drugs were sold from 2007 to 2011 to chain and independent pharmacies across the United States, mostly in cities such as Detroit, New York, Miami and Los Angeles, Assistant U.S. Attorney Charles Walsh said.