WASHINGTON, Feb 19: A computer hacker gained access to some eight million Visa and MasterCard accounts in one of the largest security breaches to affect the two credit card companies, a MasterCard spokeswoman said Tuesday.

Of the accounts, some 2.2 million registered to MasterCard users “that were possibly compromised,” the spokeswoman said. The problem was reported by a third-party merchant processor who was unable to say whether the intrusion came from the United States or overseas, said the MasterCard spokeswoman.

MasterCard International said in a separate statement that the company first became aware of the computer hacking in early February.

“In early February, MasterCard International was alerted of an intrusion to the database of a third-party merchant processor in the US,” the company said in a statement adding: “Investigations are currently underway.”

“While MasterCard International refrains from commenting on details of specific incidents, we have notified our member financial institutions of the accounts involved, so that they may monitor each account for fraud and/or reissue cards as appropriate,” MasterCard said.

MasterCard said its rules require that merchants securely encrypt cardholder information, including card numbers so that theft cannot occur.

Visa, a private for-profit association, is jointly owned by 21,000 member financial institutions around the globe.—AFP