New York (CNN Business) For the second straight day, Target checkout lines across the United States were scenes of confusion and delay. Many Targets on Sunday were unable to accept credit card payments for more than an hour.

"Like many other companies, Target uses NCR as a vendor to help accept payments, and on Sunday afternoon NCR experienced an issue at one of their data centers," Target said.

Target TGT said the issue was resolved by Sunday evening and that it wasn't related to security. It also indicated that "no payment information was compromised at any time."

NCR could not be reached for comment Sunday evening.

Target also acknowledged its customers' weekend ordeals in a short apology.