Hilton Worldwide has become the third global hotel group to be targeted by computer hackers accessing credit card data.
The group, which operates more than 4,500 hotels, has not said which hotels were impacted, but confirmed that it has identified "unauthorised malware that targeted payment card information in some point-of-sale systems" at hotels between 18 November and 5 December 2014 and 21 April and 27 July 2015.
An investigation has been launched and action taken to eradicate the potentially damaging software.
In a statement, Hilton Worldwide said it had worked with "third-party forensics experts, law enforcement and payment card companies" on the investigation, which discovered that the targeted information included cardholder names, payment card numbers, security codes and expiration dates, but not addresses or personal identification numbers (PINs).
The company advised guests and customers of Hilton Worldwide hotels on the highlighted dates to check payment card statements for any suspicious payments.
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