A mobile-based crime is occurring among mobile users of the holy city of Qom. Tricksters are getting people to call back their premium line numbers and charging mobile owners for the privilege, according to the police chief of that city, Sobhaneh Online reports. The central Iranian city's police chief, Ali Movali, said the new threat to telephone users comes as organized groups are using more sophisticated technology to trick mobile owners to give up credit and charge them. He said the offender uses an automatic calling software/machine that systematically goes through the numbers and leaves a missed call, whereby the call then responds to the premium line number and registers the charges. Movali urged caution on the side of local telephone users and urged them not to respond to unfamiliar numbers.