NEW YORK (MainStreet) — Your holiday shopping may have just taken an ugly turn. If you shopped at a Target store between November 27 and December 15 and used a debit or credit card, keep a close eye on your bank account. There's a good chance you've been hacked. Some 40 million cards accounts may be affected by an expansive security breach, according to a Target statement. The company has retained the services of a third-party forensics firm to assist in the investigation.

"Target's first priority is preserving the trust of our guests and we have moved swiftly to address this issue, so guests can shop with confidence. We regret any inconvenience this may cause," said Gregg Steinhafel, chairman, president and CEO of Target. "We take this matter very seriously and are working with law enforcement to bring those responsible to justice."

The popular national chain says the "issue has been identified and resolved." Unauthorized access to Target payment data potentially impacts purchases made at all of the 1,797 Target stores in the U.S. during the two and a half week period.

"We began investigating the incident as soon as we learned of it," a statement on the Target Website says. "We have determined that the information involved in this incident included customer name, credit or debit card number, and the card's expiration date and CVV (the three-digit security code)."

Consumers are urged by the company to keep a close eye on their accounts for signs of fraud or identity theft. Any suspicious or unusual activity should be reported to the financial institution that issued the credit or debit card.

--Written by Hal M. Bundrick for MainStreet