CitiBank was hacked and the company is admitting today that more than 210,000 of their North American customers may be affected.

The hackers are said to have broken through Citigroup’s security measures and had access to customer names, contact information, and account numbers. The hack took place in early May, but was not disclosed until now. CitiBank says that the hackers did not have access to birth dates, social security numbers, credit card expiration dates and CVV (card security) codes.

How are customers to know if their account is one that was affected by the hacking incident? Sean Kevelighan, a US based spokesman for CitiGroup, told Reuters by email. “We are contacting customers whose information was impacted. Citi has implemented enhanced procedures to prevent a recurrence of this type of event. For the security of these customers, we are not disclosing further details.”

This incident is one of several in a recent string of high profile hackings. CitiGroup was attacked previously several months ago, and Sony was recently attacked several times, causing a month long outage of Sony’s PlayStation Network.

More details to come as this story develops.