The Radisson Hotel chain is the latest American retail company to announce it has suffered a significant breach of its computer systems resulting in the compromise of credit and debit card data.

In an open letter to guests on the hotel's Web site (http://www.radisson.com/openletter/openletter.html) Radisson said that the breach had occurred for a number of months, from November 2008 until May 2009, but said the investigation had not revealed how many card numbers might have been compromised. It also revealed that the data accessed may have included the name printed on a guest's credit card or debit card, a credit or debit card number, and/or a card expiration date.

"This unauthorized access was in violation of both civil and criminal laws. Radisson has been coordinating with federal law enforcement to assist in the investigation of this incident," wrote Fredrik Korallus, chief operating officer for the hotel and resort chain.