(CNN) — Authorities are investigating an apparent credit card breach at Target stores. The Secret Service confirms it’s looking into the matter, but didn’t offer additional information.
Computer security expert Brian Krebs broke the story, and says data was stolen from Black Friday, a heavy shopping day, until this past Sunday, December 15th.
Krebs says there’s a chance the security of millions of debit and credit cards may have been compromised.
A spokeswoman from American Express says the company is “aware of the incident.”
Target has released a statement on their website regarding this incident, advising customers to keep a close eye on credit and debit card statements for any suspicious activity.