Hackers accessed about 1 per cent of Citibank's North American bank card customers, dpa cited bank officials as saying Thursday. The hacking was caught in a routine survey of the system, Citigroup said. The bank has about 21 million credit card accounts in North America. Names, account numbers and contact information, including email addresses, had been accessed. But social security numbers, dates of birth and card security codes had not been "compromised." "We are contacting customers whose information was impacted," said Sean Kevelighan, chief of public affairs for North America banking of Citigroup, in an emailed statement. He said the bank had "implemented enhanced procedures to prevent a recurrence of this type of event."