Visa has confirmed that the credit card details of "a number" of Visa customers in the US and Europe have been stolen from a US-based firm.
Some affected customers have had their cards blocked and are now unable to take advantage of the Visa slogan "Anytime, anywhere, anyway".
The company said that it is cooperating with authorities in the US and had issued a fraud alert to its member banks. It did this as soon as it was informed of an "internal security breach" at the US firm.
A Visa International spokesman refused to identify the US firm, except to say that it is a 'merchant' rather than a 'retailer'. "This is not information that we can provide," he said.
On the number of cards affected, he said: "It was not something that we would define as large."
Visa has issued 1.2bn cards and handles $2.4tn worth of transactions worldwide, 3.9 million of them per day. Last February, a hacker gained access to five million accounts in the US.
The spokesman said that the decision to reissue compromised cards is up to its 21,000 member issuing banks which would decide on a case-by-case basis. Late last week 2,000 card holders in the Netherlands found their cards blocked.
Coincidentally, yesterday the company was trumpeting the success of its secure online payment service, "Verified by Visa", which has been adopted by 80 percent of US banks and has been rolled out over Europe during the last year.