Last week’s security breach of Sony’s PlayStation Network, which has resulted in a system outage, may have resulted in PSN members’ credit card information being stolen, Sony says.

“While there is no evidence at this time that credit card data was taken, we cannot rule out the possibility,” said Patrick Seybold, senior director of corporate communications and social media, on the official PlayStation blog.

Sony is advising those who gave their credit card information to either PSN or the new Qriocity music system that hackers may have gotten their credit card number (excluding security code) and expiration date. “For your security, we encourage you to be especially aware of email, telephone, and postal mail scams that ask for personal or sensitive information,” Seybold says. “Sony will not contact you in any way, including by email, asking for your credit card number, social security number or other personally identifiable information. If you are asked for this information, you can be confident Sony is not the entity asking.”

Sony hopes to restore some PSN services within a week, Seybold says. “We have a clear path to have PlayStation Network and Qriocity systems back online,” he said. “We’re working day and night to ensure it is done as quickly as possible.”

Seybold did not offer any details on the “illegal and unauthorized intrusion into (the PlayStation) network.” The PSN has more than 75 million registered accounts in 59 countries, Sony announced earlier this month. Sony is sending an email alert to all registered account holders about the “compromise of personal information,” he said.

Since the intrusion, which occurred between April 17 and April 19, Sony has turned off all PSN and Qriocity services, engaged “an outside, recognized security firm” to investigate the incident and enhanced its network to protect against future intrusions, he said.

Seybold also recommended that users change the passwords on other services and accounts that might use the same user name or password as their PSN account. “To protect against possible identity theft or other financial loss, we encourage you to remain vigilant, to review your account statements and to monitor your credit reports,” he said.