A massive security breach of the credit card system in the United States could affect thousands of Canadian Visa card holders, a spokeswoman for Visa Canada said Saturday.

She said as many as 240,000 could be affected although it is not clear exactly which Canadian cards might have been affected by the problem at an Atlanta-based CardSystems Solutions Inc., which processes credit card and other payments for banks and merchants.

On Friday, US card companies said an unauthorized person may have accessed the accounts of up to 40 million credit card holders.

Visa Canada is watching the accounts which may have been affected, but card holders should monitor their accounts for unusual activity, the spokeswoman said.

Source: Xinhua