SAN FRANCISCO (AFP) - Hyatt Hotels on Wednesday (Dec 23) revealed that it had recently discovered malicious computer code on computers used for processing payments at locations it manages.

In a short statement, Hyatt did not disclose what, if anything, the cyber attack accomplished but said that the company immediately "launched an investigation and engaged leading third-party cyber security experts".

Hyatt also said it had strengthened the security of its systems and that "customers can feel confident using payment cards at Hyatt hotels worldwide".

The hotel group advised customers, as a precaution, to watch payment card account statements for unauthorised charges.

Cyber threats blogger Brian Krebs at KrebsonSecurity.com said in an online post that "Hyatt joins a crowded list of other hotel chains similarly breached in the past year".

Hilton and Starwood Hotels, which operates the Sheraton and Westin chains, last month (November) separately announced that payment systems had been targeted by hackers.

US hotel chain Hilton said that hackers infected some of its point-of-sale computer systems with malware crafted to steal credit card information.

Malicious code that infected registers at hotels had the potential to take cardholders' names along with card numbers, security codes and expiration dates, Hilton said in an online post.

Starwood Hotels said that hackers had infected payment systems in some of its establishments, potentially leaking customer credit card data.

The hack occurred at a "limited number" of its hotels in North America, according to Starwood, whose other well-known chains include St Regis and W Hotels.

The cyber attacks on Hilton and Starwood sounded similar to one disclosed earlier in the year by Trump Hotel Collection.

"We believe that there may have been unauthorised malware access to some of the computers that host our front desk terminals and payment card terminals in our restaurants, gift shops and other point-of-sale purchase locations at some hotels," Trump Hotel Collection said at a website devoted to details of the incident.