U.S. authorities say they've broken up a phone scam in which callers in India posed as debt collectors to bilk millions of dollars out of more than 10,000 U.S. residents.

Officials say callers used threats of arrest or the loss of their jobs, and that the first-of-its-kind investigation may have only uncovered the tip of the iceberg.

Federal Trade Commission official Steven Baker says callers drew on personal data snatched from payday loan websites, though it's uncertain how that information was obtained. More than 20 million calls may have been placed over the past two years, with collectors demanding between $300 and $2,000 per call.

Baker says the fraud with so many millions of calls flooding in from India is something investigators haven't seen before and was fostered in part by the plummeting costs of international calls.

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