(RNN) - P.F. Chang's China Bistro said it is investigating reports of a data breach, but stopped short of confirming a breach.
Security website Krebs On Security reported that thousands of stolen credit and debit cards used at P.F. Chang's locations were up for sale on an underground website. The stolen cards were used by customers between March and May 19, 2014, according to the site.
In a statement, the restaurant said "P.F. Chang's takes these matters very seriously and is currently investigating the situation, working with the authorities to learn more. We will provide an update as soon as we have additional information."
It's not clear how many or which P.F. Chang's restaurants may have been affected.
Krebs on Security reported that thieves typically hack into registers and plant software that records stripe data when cards are swiped.
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