The Secret Service was investigating a possible data breach involving millions of shoppers using credit and debit cards at Target stores across the country.
Secret Service spokesman Brian Leary confirmed the investigation to CNN on Wednesday, but declined to comment further.
A report from security researcher Brian Krebs states that Target suffered a data breach around Black Friday “potentially involving millions of customer credit and debit card records.”
The Secret Service would not elaborate of the type of breach, but Krebs reported it may have involved the machines used to swipe shoppers’ cards.
Those potentially affected were in-store customers, not online shoppers.
CNN contributed to this report.