Hyatt says it found malicious software in about 250 of its hotels that may have taken customers' credit- and debit-card numbers and other information.
It's the first time the hotel operator listed the hotels affected since it first announced it found malware at its hotels in December.
Several of the hotel chains are located in New York, including one in Buffalo and Rochester and five in New York City.
A Hyatt spokeswoman says the hotel chain does not know at this time how many customers were affected.
Hyatt Hotels Corp. says the malware was present between July and December at payment-processing systems at its restaurants, spas, front desks and other areas.
The malware was found at many of its brands, including the Park Hyatt, Hyatt Regency and Andaz. About 100 of the hotels affected were in the U.S., the rest were abroad in cities including London, Paris and Shanghai.
The Chicago company has about 630 properties.
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