SAN FRANCISCO - Hyatt Hotels (H) says it found malicious software on the computer system that processes customer payments, raising the possibility that hackers may have obtained credit card numbers or other sensitive information.

The resort chain is advising customers to review their payment card statements, although it has not said if any customer data was stolen. Hyatt spokeswoman Stephanie Sheppard said in an email that the malware was discovered Nov. 30, but she didn't say why the company waited three weeks to report the discovery on Wednesday.

Hyatt is the latest of several major hotel chains to report this year that hackers had attacked their computers. The Hilton (HLT), Starwood (HOT), Mandarin Oriental and Trump Collection chains have previously acknowledged finding malware in their payment systems. While some of the companies haven't disclosed details, Starwood acknowledged last month that the malware enabled "unauthorized parties to access payment card data" for some of its customers.

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At the Hyatt chain, Sheppard told The Associated Press, "the investigation is ongoing, and we'll have more information once it is complete."

Hyatt also said it has hired outside experts to help investigate the malware and has taken steps to increase security on its computer systems.

The Chicago-based company owns, manages or franchises a portfolio of 627 properties in 52 countries. Sheppard said the malware was found on computers that process payments for the hotels that Hyatt manages, although she did not say how many.

Hyatt is promising to provide updates on its website, at hyatt.com/protectingourcustomers.