A German data protection official has called for Facebook to delete biometric profiles of people stored without their explicit consent.

In short, he wants Facebook to delete users' faces from its databases.

The Hamburg Commissioner for Data Protection said Wednesday that talks to bring Facebook's business practice in line with German and European privacy rules had failed.

Johannes Caspar says he is now re-opening a stalled probe of the Menlo Park, California-based company "in order to find a legally sound solution with regard to the use of biometric data" that he says can be used to automatically identify individuals.

He says "Facebook will be obliged to delete this data unless it obtains approval by all concerned users."

Calls to Facebook representatives in London weren't immediately answered.