Method and device for carrying out security procedures involving mobile stations in hybrid cellular telecommunication systems

A method (300) for carrying out a security procedure with a mobile station, where a hybrid cellular telecommunication system communicates with a mobile station (301) and the hybrid cellular telecommunication system communicates with a cellular network (308). The method is characterized in that the cellular network carries out the security procedure with the mobile station, the data related to the security procedure is transferred between the cellular network and the mobile station via the hybrid cellular telecommunication system, and the decision of triggering the security procedure of the cellular network is made outside the cellular network (309). The invention also relates to a network element (510) in the hybrid cellular telecommunication system that triggers the security procedure and to a network element (500) in the cellular network that carries out the security procedure after receiving a triggering signal.