BERLIN - A German privacy watchdog is demanding answers from Apple Inc over whether its iPhones and iPads are secretly collecting data on users' locations.

Thomas Kranig, head of the data protection authority for the state of Bavaria, where Apple has its German headquarters, said in an interview published in Saturday's Sueddeutsche Zeitung that the company has until May 10 to respond.

Apple has come under pressure since researchers raised questions about how tracking data gathered by iPhones and iPads is being handled.

Germany has some of the world's strictest privacy laws and has tangled with Google, Facebook and other US-based technology companies over personal data and how it's used.

Calls to Kranig and to Apple were not immediately returned.