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

In short, the Hamburg Commissioner for Data Protection Johannes Caspar wants Facebook to delete users' faces from its databases.

The Commissioner said today that talks to bring Facebook's business practice in line with German and European privacy rules had failed.

Mr 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 were not immediately answered.