The creator of Rock Band and Dance Central is warning customers who have an account on its websites — rockband.com, dancecentral.com and creators.rockband.com — of an "apparent attack" on its servers.

Harmonix alerted account holders via email today, writing, "We are investigating an apparent attack on our servers that we detected this week."

"The security of your Harmonix user information is very important to us," the email reads. "We've taken the sites down while we investigate this incident and determine how our systems and the information we maintain may have been compromised. At this time, we have not found that any of our users' information has been published or misused."

The game developer has disabled users' account passwords and will require account holders to reset them. "If you have been using your old Harmonix password on other sites, we recommend that you change those passwords too," the email reads.

Harmonix writes that its websites don't store users' credit card information or social security numbers.

The websites for both Rock Band and Dance Central currently show maintenance messages, asking visitors to refer to Harmonix's Facebook and Twitter accounts for updates.