Two Android phone users in the US have sued Google over claims their phones contained secret files that stored and transmitted data about their movements.
In a complaint filed 27 April in federal court in Detroit, the two residents of Oakland County in Michigan said that their HTC Inspire 4G phones, which use Google’s Android OS, track their movements "just as if by a tracking device for which a court-ordered warrant would ordinarily be required."
The plaintiffs seek $50m in damages and a court order requiring Google to stop tracking its users.
They said in teh complaint that they also seek to represent other Android phone users in a class-action lawsuit.
Earlier Google had admitted that it tracked the movement of its Android users, but with prior permission and anonymously.
The company had said that it did so to provide customised services such as maps and searches for shops or restaurants, and to study traffic on various roads.
Google spokesman Mike Nelson had said, "Phones know where you are, and they need to for many of the services we offer."
The company said, "All location sharing on Android is opt-in by the user. We provide users with notice and control over the collection, sharing and use of location in order to provide a better mobile experience on Android devices."
"Any location data that is sent back to Google location servers is anonymised and is not tied or traceable to a specific user."
Last week privacy concerns were raised after two British security researchers, Alisdair Allan and Pete Warden, identified that Apple iPhones had secret unencrypted files in them which tracked the movements of users without their knowledge.