In a surprising move, LevelUp is cutting its ties to Facebook, citing security concerns.

The mobile payments service sent an email yesterday to all users that signed up with LevelUp via Facebook telling them they must reset their passwords. The text of the email is below:

LevelUp is removing the ability to register or log in with Facebook. While you can still post to Facebook from within LevelUp if you’d like, you’ll no longer be able to use Facebook to log in. After careful evaluation, we’ve decided to make this change in order to strengthen LevelUp’s overall security architecture.

It looks like you originally registered for LevelUp via Facebook Connect which means you might not remember your LevelUp password.

To make sure that you can always log in to LevelUp, please click the button below to reset and select a new password.

It is not clear by what date the password reset must be done, but it seems LevelUp has already removed the “Log in with Facebook” option from its smartphone apps. It is still possible to join LevelUp via Facebook on LevelUp’s website, however, as you can see at left. But since LevelUp is used almost entirely on mobile, that seems curious. “These options will slowly be removed,” according to the company. The ability to share LevelUp experiences on Facebook will remain, however.

Other financial mobile apps, such as Moven, retain the ability to log in with Facebook via mobile, and indeed, it seems to have become an increasingly common feature of mobile apps over the past year. Is LevelUp’s move a sign of Facebook’s decline among LevelUp’s predominantly younger userbase, or fears about Facebook’s incursion into mobile commerce, or simply a security matter, as the company says?

Logins using Twitter or Facebook or more recently, Amazon, provide convenience for the customer, who already has too many logins to remember, but also make the app borrowing Facebook’s login credentials dependent on Facebook. The media is full of stories of young people ditching Facebook for Instagram (owned by Facebook), Snapchat and the like, and perhaps this loss of young people is beginning to erode Facebook’s partnerships with external sites.

LevelUp told Bank Innovation that it “is committed to making sure that using the app gives our users a secure and seamless experience. We found that Facebook may decrease the level of security that we strive for, and we’ve removed it to get closer to this goal.”

Learn more about what’s next in banking at Bank Innovation 2014 on March 3-4 in Seattle. Request an invitation here.