WOODBURY - Mastercard and Visa are warning customers after they say a massive credit card breach could have leaked the personal information of more than 10 million people.

The credit card companies say hackers breached Global Payments, an Atlanta-based credit card processor. Officials say the security breach occurred sometime between Jan. 21 and Feb. 25, according to notices that Visa and MasterCard recently sent to banks.

Investigators say the hackers also swiped social security numbers.

Both companies informed customers that the card issuers themselves will be responsible for all fraudulent chargess.

Financial experts advise credit card users to pay attention to all online transactions, check credit reports at least once a year and be aware of suspicious emails.