A new finding of the location services of IT giant Apple's iPhone handsets have raised concerns about information security in China.
Tests by information security engineers show user's locations are stored in hidden directories on the phones.
Engineers with the China Information Technology Security evaluation Center have been focusing on the iPhone feature and how it collects users' locations.
Wang Jiajie, an engineer with the center, says they are concerned about the results they have discovered.
"Firstly, we connect the iPhone to a computer via a USB data link. Then with some special tools, we can view some system directories that normal users cannot see. In the system directories, we found a hidden directory which can record user's locations at different times."
Wang explains that an iPhone feature called 'Frequent Locations' can record locations users have visited frequently and the exact times of the visits.
Engineers warn that even if users choose to disable this feature the phone continues to record their locations, which is an information security risk.
Apple's iphone products are very popular in China, especially among the young people.
China is home to the world's biggest population at 1.3 billion, and it's an important revenue stream for Apple.