Hyatt Hotels Corporation has identified malware on computers that operate the payment processing systems for Hyatt-managed locations.
The company launched an investigation and has engaged leading third-party cyber security experts.
The investigation is ongoing, and updates will be posted online.
Hyatt claims it has has taken steps to strengthen the security of its systems, and customers can feel confident using payment cards at Hyatt hotels worldwide.
Customers are being advised to review their payment card account statements closely and report any unauthorised charges to their card issuer immediately.
Payment card rules generally provide that cardholders are not responsible for unauthoried charges that are timely reported.