German consumer groups said Thursday they will file a lawsuit against Facebook unless the social network changes its terms of service.

The Federation of German Consumer Organizations said it has sent a cease-and-desist letter to Facebook's European headquarters in Ireland.

The letter cites 19 clauses in the company's terms of service and data protection guidelines that the consumer groups claim breach German law.

German Justice Minister Heiko Maas backed the complaint, saying Facebook's data protection rules are too vague. He said users should be able to opt out of certain requirements without having to quit Facebook entirely.

The California-based company has faced regular legal challenges from privacy advocates in Europe.

Facebook told The Associated Press in an emailed statement it was reviewing the complaint, but was surprised that it "focused on settled terms and features that have been part of Facebook and other online services for the past 10 years, such as real-name policies."

"We recently updated our terms and policies to make them more clear and concise, to reflect new product features and to highlight how we're expanding people's control over advertising," the company said. "We're confident the updates comply with applicable laws."