An elaborate phone scam aimed at stealing credit card and ATM information is targeting Los Angeles County residents, District Attorney Steve Cooley warned Tuesday.

The scam was uncovered after Cooley's own staffers received some of the calls over the last few weeks.

Cooley said the scam involves robocalls that instruct recipients to call a number to review their bank information with a live operator.

The targets are then asked to provide information such as numbers for their bank account, credit card and ATM code. The operators are often based in other countries.

"Your bank account can be drained by someone in a foreign country," Cooley said, adding that legitimate banks don't call to verify personal information.

Such scams are common during the heavy spending period of the holidays because legitimate credit card companies often double-check customers' expenditures via phone calls.

Additionally, the district attorney believes that with more outsourcing of bank work, personal information might be more readily available for exploitation.

"It's recurring," Cooley said. "But it seems to have picked up with the outsourcing of banking information work to foreign countries."

Cooley says his staff didn't lose any money, but that the losses for those who were affected can be in the "thousands to millions of dollars."